diff --git a/command.go b/command.go
index fcea708..f325697 100644
--- a/command.go
+++ b/command.go
@@ -1,6 +1,7 @@
 package redis
 
 import (
+	"bytes"
 	"fmt"
 	"strconv"
 	"strings"
@@ -28,7 +29,7 @@ var (
 )
 
 type Cmder interface {
-	args() []string
+	args() []interface{}
 	parseReply(*bufio.Reader) error
 	setErr(error)
 	reset()
@@ -38,7 +39,7 @@ type Cmder interface {
 	clusterKey() string
 
 	Err() error
-	String() string
+	fmt.Stringer
 }
 
 func setCmdsErr(cmds []Cmder, e error) {
@@ -54,12 +55,21 @@ func resetCmds(cmds []Cmder) {
 }
 
 func cmdString(cmd Cmder, val interface{}) string {
-	s := strings.Join(cmd.args(), " ")
+	var ss []string
+	for _, arg := range cmd.args() {
+		ss = append(ss, fmt.Sprint(arg))
+	}
+	s := strings.Join(ss, " ")
 	if err := cmd.Err(); err != nil {
 		return s + ": " + err.Error()
 	}
 	if val != nil {
-		return s + ": " + fmt.Sprint(val)
+		switch vv := val.(type) {
+		case []byte:
+			return s + ": " + string(vv)
+		default:
+			return s + ": " + fmt.Sprint(val)
+		}
 	}
 	return s
 
@@ -68,7 +78,7 @@ func cmdString(cmd Cmder, val interface{}) string {
 //------------------------------------------------------------------------------
 
 type baseCmd struct {
-	_args []string
+	_args []interface{}
 
 	err error
 
@@ -84,7 +94,7 @@ func (cmd *baseCmd) Err() error {
 	return nil
 }
 
-func (cmd *baseCmd) args() []string {
+func (cmd *baseCmd) args() []interface{} {
 	return cmd._args
 }
 
@@ -102,7 +112,7 @@ func (cmd *baseCmd) writeTimeout() *time.Duration {
 
 func (cmd *baseCmd) clusterKey() string {
 	if cmd._clusterKeyPos > 0 && cmd._clusterKeyPos < len(cmd._args) {
-		return cmd._args[cmd._clusterKeyPos]
+		return fmt.Sprint(cmd._args[cmd._clusterKeyPos])
 	}
 	return ""
 }
@@ -123,7 +133,7 @@ type Cmd struct {
 	val interface{}
 }
 
-func NewCmd(args ...string) *Cmd {
+func NewCmd(args ...interface{}) *Cmd {
 	return &Cmd{baseCmd: baseCmd{_args: args}}
 }
 
@@ -146,6 +156,11 @@ func (cmd *Cmd) String() string {
 
 func (cmd *Cmd) parseReply(rd *bufio.Reader) error {
 	cmd.val, cmd.err = parseReply(rd, parseSlice)
+	// Convert to string to preserve old behaviour.
+	// TODO: remove in v4
+	if v, ok := cmd.val.([]byte); ok {
+		cmd.val = string(v)
+	}
 	return cmd.err
 }
 
@@ -157,7 +172,7 @@ type SliceCmd struct {
 	val []interface{}
 }
 
-func NewSliceCmd(args ...string) *SliceCmd {
+func NewSliceCmd(args ...interface{}) *SliceCmd {
 	return &SliceCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
@@ -196,11 +211,11 @@ type StatusCmd struct {
 	val string
 }
 
-func NewStatusCmd(args ...string) *StatusCmd {
+func NewStatusCmd(args ...interface{}) *StatusCmd {
 	return &StatusCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
-func newKeylessStatusCmd(args ...string) *StatusCmd {
+func newKeylessStatusCmd(args ...interface{}) *StatusCmd {
 	return &StatusCmd{baseCmd: baseCmd{_args: args}}
 }
 
@@ -227,7 +242,7 @@ func (cmd *StatusCmd) parseReply(rd *bufio.Reader) error {
 		cmd.err = err
 		return err
 	}
-	cmd.val = v.(string)
+	cmd.val = string(v.([]byte))
 	return nil
 }
 
@@ -239,7 +254,7 @@ type IntCmd struct {
 	val int64
 }
 
-func NewIntCmd(args ...string) *IntCmd {
+func NewIntCmd(args ...interface{}) *IntCmd {
 	return &IntCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
@@ -279,7 +294,7 @@ type DurationCmd struct {
 	precision time.Duration
 }
 
-func NewDurationCmd(precision time.Duration, args ...string) *DurationCmd {
+func NewDurationCmd(precision time.Duration, args ...interface{}) *DurationCmd {
 	return &DurationCmd{
 		precision: precision,
 		baseCmd:   baseCmd{_args: args, _clusterKeyPos: 1},
@@ -321,7 +336,7 @@ type BoolCmd struct {
 	val bool
 }
 
-func NewBoolCmd(args ...string) *BoolCmd {
+func NewBoolCmd(args ...interface{}) *BoolCmd {
 	return &BoolCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
@@ -342,6 +357,8 @@ func (cmd *BoolCmd) String() string {
 	return cmdString(cmd, cmd.val)
 }
 
+var ok = []byte("OK")
+
 func (cmd *BoolCmd) parseReply(rd *bufio.Reader) error {
 	v, err := parseReply(rd, nil)
 	// `SET key value NX` returns nil when key already exists.
@@ -357,8 +374,8 @@ func (cmd *BoolCmd) parseReply(rd *bufio.Reader) error {
 	case int64:
 		cmd.val = vv == 1
 		return nil
-	case string:
-		cmd.val = vv == "OK"
+	case []byte:
+		cmd.val = bytes.Equal(vv, ok)
 		return nil
 	default:
 		return fmt.Errorf("got %T, wanted int64 or string")
@@ -370,23 +387,27 @@ func (cmd *BoolCmd) parseReply(rd *bufio.Reader) error {
 type StringCmd struct {
 	baseCmd
 
-	val string
+	val []byte
 }
 
-func NewStringCmd(args ...string) *StringCmd {
+func NewStringCmd(args ...interface{}) *StringCmd {
 	return &StringCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
 func (cmd *StringCmd) reset() {
-	cmd.val = ""
+	cmd.val = nil
 	cmd.err = nil
 }
 
 func (cmd *StringCmd) Val() string {
-	return cmd.val
+	return string(cmd.val)
 }
 
 func (cmd *StringCmd) Result() (string, error) {
+	return cmd.Val(), cmd.err
+}
+
+func (cmd *StringCmd) Bytes() ([]byte, error) {
 	return cmd.val, cmd.err
 }
 
@@ -394,21 +415,28 @@ func (cmd *StringCmd) Int64() (int64, error) {
 	if cmd.err != nil {
 		return 0, cmd.err
 	}
-	return strconv.ParseInt(cmd.val, 10, 64)
+	return strconv.ParseInt(cmd.Val(), 10, 64)
 }
 
 func (cmd *StringCmd) Uint64() (uint64, error) {
 	if cmd.err != nil {
 		return 0, cmd.err
 	}
-	return strconv.ParseUint(cmd.val, 10, 64)
+	return strconv.ParseUint(cmd.Val(), 10, 64)
 }
 
 func (cmd *StringCmd) Float64() (float64, error) {
 	if cmd.err != nil {
 		return 0, cmd.err
 	}
-	return strconv.ParseFloat(cmd.val, 64)
+	return strconv.ParseFloat(cmd.Val(), 64)
+}
+
+func (cmd *StringCmd) Scan(val interface{}) error {
+	if cmd.err != nil {
+		return cmd.err
+	}
+	return scan(cmd.val, val)
 }
 
 func (cmd *StringCmd) String() string {
@@ -421,7 +449,9 @@ func (cmd *StringCmd) parseReply(rd *bufio.Reader) error {
 		cmd.err = err
 		return err
 	}
-	cmd.val = v.(string)
+	b := v.([]byte)
+	cmd.val = make([]byte, len(b))
+	copy(cmd.val, b)
 	return nil
 }
 
@@ -433,7 +463,7 @@ type FloatCmd struct {
 	val float64
 }
 
-func NewFloatCmd(args ...string) *FloatCmd {
+func NewFloatCmd(args ...interface{}) *FloatCmd {
 	return &FloatCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
@@ -456,7 +486,7 @@ func (cmd *FloatCmd) parseReply(rd *bufio.Reader) error {
 		cmd.err = err
 		return err
 	}
-	cmd.val, cmd.err = strconv.ParseFloat(v.(string), 64)
+	cmd.val, cmd.err = strconv.ParseFloat(string(v.([]byte)), 64)
 	return cmd.err
 }
 
@@ -468,7 +498,7 @@ type StringSliceCmd struct {
 	val []string
 }
 
-func NewStringSliceCmd(args ...string) *StringSliceCmd {
+func NewStringSliceCmd(args ...interface{}) *StringSliceCmd {
 	return &StringSliceCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
@@ -507,7 +537,7 @@ type BoolSliceCmd struct {
 	val []bool
 }
 
-func NewBoolSliceCmd(args ...string) *BoolSliceCmd {
+func NewBoolSliceCmd(args ...interface{}) *BoolSliceCmd {
 	return &BoolSliceCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
@@ -546,7 +576,7 @@ type StringStringMapCmd struct {
 	val map[string]string
 }
 
-func NewStringStringMapCmd(args ...string) *StringStringMapCmd {
+func NewStringStringMapCmd(args ...interface{}) *StringStringMapCmd {
 	return &StringStringMapCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
@@ -585,7 +615,7 @@ type StringIntMapCmd struct {
 	val map[string]int64
 }
 
-func NewStringIntMapCmd(args ...string) *StringIntMapCmd {
+func NewStringIntMapCmd(args ...interface{}) *StringIntMapCmd {
 	return &StringIntMapCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
@@ -624,7 +654,7 @@ type ZSliceCmd struct {
 	val []Z
 }
 
-func NewZSliceCmd(args ...string) *ZSliceCmd {
+func NewZSliceCmd(args ...interface{}) *ZSliceCmd {
 	return &ZSliceCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
@@ -664,7 +694,7 @@ type ScanCmd struct {
 	keys   []string
 }
 
-func NewScanCmd(args ...string) *ScanCmd {
+func NewScanCmd(args ...interface{}) *ScanCmd {
 	return &ScanCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
@@ -720,7 +750,7 @@ type ClusterSlotCmd struct {
 	val []ClusterSlotInfo
 }
 
-func NewClusterSlotCmd(args ...string) *ClusterSlotCmd {
+func NewClusterSlotCmd(args ...interface{}) *ClusterSlotCmd {
 	return &ClusterSlotCmd{baseCmd: baseCmd{_args: args, _clusterKeyPos: 1}}
 }
 
diff --git a/command_test.go b/command_test.go
index c1c968e..1218724 100644
--- a/command_test.go
+++ b/command_test.go
@@ -26,7 +26,7 @@ var _ = Describe("Command", func() {
 		Expect(client.Close()).NotTo(HaveOccurred())
 	})
 
-	It("should have a plain string result", func() {
+	It("should implement Stringer", func() {
 		set := client.Set("foo", "bar", 0)
 		Expect(set.String()).To(Equal("SET foo bar: OK"))
 
@@ -117,6 +117,13 @@ var _ = Describe("Command", func() {
 		Expect(f).To(Equal(float64(10)))
 	})
 
+	It("Cmd should return string", func() {
+		cmd := redis.NewCmd("PING")
+		client.Process(cmd)
+		Expect(cmd.Err()).NotTo(HaveOccurred())
+		Expect(cmd.Val()).To(Equal("PONG"))
+	})
+
 	Describe("races", func() {
 		var C, N = 10, 1000
 		if testing.Short() {
diff --git a/commands.go b/commands.go
index 7f4cbe0..56167d5 100644
--- a/commands.go
+++ b/commands.go
@@ -7,14 +7,18 @@ import (
 	"time"
 )
 
-func formatFloat(f float64) string {
-	return strconv.FormatFloat(f, 'f', -1, 64)
-}
-
 func formatInt(i int64) string {
 	return strconv.FormatInt(i, 10)
 }
 
+func formatUint(i uint64) string {
+	return strconv.FormatUint(i, 10)
+}
+
+func formatFloat(f float64) string {
+	return strconv.FormatFloat(f, 'f', -1, 64)
+}
+
 func readTimeout(timeout time.Duration) time.Duration {
 	if timeout == 0 {
 		return 0
@@ -22,14 +26,6 @@ func readTimeout(timeout time.Duration) time.Duration {
 	return timeout + time.Second
 }
 
-type commandable struct {
-	process func(cmd Cmder)
-}
-
-func (c *commandable) Process(cmd Cmder) {
-	c.process(cmd)
-}
-
 func usePrecise(dur time.Duration) bool {
 	return dur < time.Second || dur%time.Second != 0
 }
@@ -41,7 +37,7 @@ func formatMs(dur time.Duration) string {
 			dur, time.Millisecond,
 		)
 	}
-	return strconv.FormatInt(int64(dur/time.Millisecond), 10)
+	return formatInt(int64(dur / time.Millisecond))
 }
 
 func formatSec(dur time.Duration) string {
@@ -51,7 +47,15 @@ func formatSec(dur time.Duration) string {
 			dur, time.Second,
 		)
 	}
-	return strconv.FormatInt(int64(dur/time.Second), 10)
+	return formatInt(int64(dur / time.Second))
+}
+
+type commandable struct {
+	process func(cmd Cmder)
+}
+
+func (c *commandable) Process(cmd Cmder) {
+	c.process(cmd)
 }
 
 //------------------------------------------------------------------------------
@@ -80,7 +84,7 @@ func (c *commandable) Quit() *StatusCmd {
 }
 
 func (c *commandable) Select(index int64) *StatusCmd {
-	cmd := newKeylessStatusCmd("SELECT", strconv.FormatInt(index, 10))
+	cmd := newKeylessStatusCmd("SELECT", formatInt(index))
 	c.Process(cmd)
 	return cmd
 }
@@ -88,7 +92,11 @@ func (c *commandable) Select(index int64) *StatusCmd {
 //------------------------------------------------------------------------------
 
 func (c *commandable) Del(keys ...string) *IntCmd {
-	args := append([]string{"DEL"}, keys...)
+	args := make([]interface{}, 1+len(keys))
+	args[0] = "DEL"
+	for i, key := range keys {
+		args[1+i] = key
+	}
 	cmd := NewIntCmd(args...)
 	c.Process(cmd)
 	return cmd
@@ -113,7 +121,7 @@ func (c *commandable) Expire(key string, expiration time.Duration) *BoolCmd {
 }
 
 func (c *commandable) ExpireAt(key string, tm time.Time) *BoolCmd {
-	cmd := NewBoolCmd("EXPIREAT", key, strconv.FormatInt(tm.Unix(), 10))
+	cmd := NewBoolCmd("EXPIREAT", key, formatInt(tm.Unix()))
 	c.Process(cmd)
 	return cmd
 }
@@ -130,7 +138,7 @@ func (c *commandable) Migrate(host, port, key string, db int64, timeout time.Dur
 		host,
 		port,
 		key,
-		strconv.FormatInt(db, 10),
+		formatInt(db),
 		formatMs(timeout),
 	)
 	cmd._clusterKeyPos = 3
@@ -140,13 +148,18 @@ func (c *commandable) Migrate(host, port, key string, db int64, timeout time.Dur
 }
 
 func (c *commandable) Move(key string, db int64) *BoolCmd {
-	cmd := NewBoolCmd("MOVE", key, strconv.FormatInt(db, 10))
+	cmd := NewBoolCmd("MOVE", key, formatInt(db))
 	c.Process(cmd)
 	return cmd
 }
 
 func (c *commandable) ObjectRefCount(keys ...string) *IntCmd {
-	args := append([]string{"OBJECT", "REFCOUNT"}, keys...)
+	args := make([]interface{}, 2+len(keys))
+	args[0] = "OBJECT"
+	args[1] = "REFCOUNT"
+	for i, key := range keys {
+		args[2+i] = key
+	}
 	cmd := NewIntCmd(args...)
 	cmd._clusterKeyPos = 2
 	c.Process(cmd)
@@ -154,7 +167,12 @@ func (c *commandable) ObjectRefCount(keys ...string) *IntCmd {
 }
 
 func (c *commandable) ObjectEncoding(keys ...string) *StringCmd {
-	args := append([]string{"OBJECT", "ENCODING"}, keys...)
+	args := make([]interface{}, 2+len(keys))
+	args[0] = "OBJECT"
+	args[1] = "ENCODING"
+	for i, key := range keys {
+		args[2+i] = key
+	}
 	cmd := NewStringCmd(args...)
 	cmd._clusterKeyPos = 2
 	c.Process(cmd)
@@ -162,7 +180,12 @@ func (c *commandable) ObjectEncoding(keys ...string) *StringCmd {
 }
 
 func (c *commandable) ObjectIdleTime(keys ...string) *DurationCmd {
-	args := append([]string{"OBJECT", "IDLETIME"}, keys...)
+	args := make([]interface{}, 2+len(keys))
+	args[0] = "OBJECT"
+	args[1] = "IDLETIME"
+	for i, key := range keys {
+		args[2+i] = key
+	}
 	cmd := NewDurationCmd(time.Second, args...)
 	cmd._clusterKeyPos = 2
 	c.Process(cmd)
@@ -185,7 +208,7 @@ func (c *commandable) PExpireAt(key string, tm time.Time) *BoolCmd {
 	cmd := NewBoolCmd(
 		"PEXPIREAT",
 		key,
-		strconv.FormatInt(tm.UnixNano()/int64(time.Millisecond), 10),
+		formatInt(tm.UnixNano()/int64(time.Millisecond)),
 	)
 	c.Process(cmd)
 	return cmd
@@ -219,7 +242,7 @@ func (c *commandable) Restore(key string, ttl int64, value string) *StatusCmd {
 	cmd := NewStatusCmd(
 		"RESTORE",
 		key,
-		strconv.FormatInt(ttl, 10),
+		formatInt(ttl),
 		value,
 	)
 	c.Process(cmd)
@@ -236,7 +259,7 @@ type Sort struct {
 }
 
 func (c *commandable) Sort(key string, sort Sort) *StringSliceCmd {
-	args := []string{"SORT", key}
+	args := []interface{}{"SORT", key}
 	if sort.By != "" {
 		args = append(args, "BY", sort.By)
 	}
@@ -273,12 +296,12 @@ func (c *commandable) Type(key string) *StatusCmd {
 }
 
 func (c *commandable) Scan(cursor int64, match string, count int64) *ScanCmd {
-	args := []string{"SCAN", strconv.FormatInt(cursor, 10)}
+	args := []interface{}{"SCAN", formatInt(cursor)}
 	if match != "" {
 		args = append(args, "MATCH", match)
 	}
 	if count > 0 {
-		args = append(args, "COUNT", strconv.FormatInt(count, 10))
+		args = append(args, "COUNT", formatInt(count))
 	}
 	cmd := NewScanCmd(args...)
 	c.Process(cmd)
@@ -286,12 +309,12 @@ func (c *commandable) Scan(cursor int64, match string, count int64) *ScanCmd {
 }
 
 func (c *commandable) SScan(key string, cursor int64, match string, count int64) *ScanCmd {
-	args := []string{"SSCAN", key, strconv.FormatInt(cursor, 10)}
+	args := []interface{}{"SSCAN", key, formatInt(cursor)}
 	if match != "" {
 		args = append(args, "MATCH", match)
 	}
 	if count > 0 {
-		args = append(args, "COUNT", strconv.FormatInt(count, 10))
+		args = append(args, "COUNT", formatInt(count))
 	}
 	cmd := NewScanCmd(args...)
 	c.Process(cmd)
@@ -299,12 +322,12 @@ func (c *commandable) SScan(key string, cursor int64, match string, count int64)
 }
 
 func (c *commandable) HScan(key string, cursor int64, match string, count int64) *ScanCmd {
-	args := []string{"HSCAN", key, strconv.FormatInt(cursor, 10)}
+	args := []interface{}{"HSCAN", key, formatInt(cursor)}
 	if match != "" {
 		args = append(args, "MATCH", match)
 	}
 	if count > 0 {
-		args = append(args, "COUNT", strconv.FormatInt(count, 10))
+		args = append(args, "COUNT", formatInt(count))
 	}
 	cmd := NewScanCmd(args...)
 	c.Process(cmd)
@@ -312,12 +335,12 @@ func (c *commandable) HScan(key string, cursor int64, match string, count int64)
 }
 
 func (c *commandable) ZScan(key string, cursor int64, match string, count int64) *ScanCmd {
-	args := []string{"ZSCAN", key, strconv.FormatInt(cursor, 10)}
+	args := []interface{}{"ZSCAN", key, formatInt(cursor)}
 	if match != "" {
 		args = append(args, "MATCH", match)
 	}
 	if count > 0 {
-		args = append(args, "COUNT", strconv.FormatInt(count, 10))
+		args = append(args, "COUNT", formatInt(count))
 	}
 	cmd := NewScanCmd(args...)
 	c.Process(cmd)
@@ -337,12 +360,12 @@ type BitCount struct {
 }
 
 func (c *commandable) BitCount(key string, bitCount *BitCount) *IntCmd {
-	args := []string{"BITCOUNT", key}
+	args := []interface{}{"BITCOUNT", key}
 	if bitCount != nil {
 		args = append(
 			args,
-			strconv.FormatInt(bitCount.Start, 10),
-			strconv.FormatInt(bitCount.End, 10),
+			formatInt(bitCount.Start),
+			formatInt(bitCount.End),
 		)
 	}
 	cmd := NewIntCmd(args...)
@@ -351,8 +374,13 @@ func (c *commandable) BitCount(key string, bitCount *BitCount) *IntCmd {
 }
 
 func (c *commandable) bitOp(op, destKey string, keys ...string) *IntCmd {
-	args := []string{"BITOP", op, destKey}
-	args = append(args, keys...)
+	args := make([]interface{}, 3+len(keys))
+	args[0] = "BITOP"
+	args[1] = op
+	args[2] = destKey
+	for i, key := range keys {
+		args[3+i] = key
+	}
 	cmd := NewIntCmd(args...)
 	c.Process(cmd)
 	return cmd
@@ -375,13 +403,17 @@ func (c *commandable) BitOpNot(destKey string, key string) *IntCmd {
 }
 
 func (c *commandable) BitPos(key string, bit int64, pos ...int64) *IntCmd {
-	args := []string{"BITPOS", key, formatInt(bit)}
+	args := make([]interface{}, 3+len(pos))
+	args[0] = "BITPOS"
+	args[1] = key
+	args[2] = formatInt(bit)
 	switch len(pos) {
 	case 0:
 	case 1:
-		args = append(args, formatInt(pos[0]))
+		args[3] = formatInt(pos[0])
 	case 2:
-		args = append(args, formatInt(pos[0]), formatInt(pos[1]))
+		args[3] = formatInt(pos[0])
+		args[4] = formatInt(pos[1])
 	default:
 		panic("too many arguments")
 	}
@@ -397,7 +429,7 @@ func (c *commandable) Decr(key string) *IntCmd {
 }
 
 func (c *commandable) DecrBy(key string, decrement int64) *IntCmd {
-	cmd := NewIntCmd("DECRBY", key, strconv.FormatInt(decrement, 10))
+	cmd := NewIntCmd("DECRBY", key, formatInt(decrement))
 	c.Process(cmd)
 	return cmd
 }
@@ -409,7 +441,7 @@ func (c *commandable) Get(key string) *StringCmd {
 }
 
 func (c *commandable) GetBit(key string, offset int64) *IntCmd {
-	cmd := NewIntCmd("GETBIT", key, strconv.FormatInt(offset, 10))
+	cmd := NewIntCmd("GETBIT", key, formatInt(offset))
 	c.Process(cmd)
 	return cmd
 }
@@ -418,14 +450,14 @@ func (c *commandable) GetRange(key string, start, end int64) *StringCmd {
 	cmd := NewStringCmd(
 		"GETRANGE",
 		key,
-		strconv.FormatInt(start, 10),
-		strconv.FormatInt(end, 10),
+		formatInt(start),
+		formatInt(end),
 	)
 	c.Process(cmd)
 	return cmd
 }
 
-func (c *commandable) GetSet(key, value string) *StringCmd {
+func (c *commandable) GetSet(key string, value interface{}) *StringCmd {
 	cmd := NewStringCmd("GETSET", key, value)
 	c.Process(cmd)
 	return cmd
@@ -438,7 +470,7 @@ func (c *commandable) Incr(key string) *IntCmd {
 }
 
 func (c *commandable) IncrBy(key string, value int64) *IntCmd {
-	cmd := NewIntCmd("INCRBY", key, strconv.FormatInt(value, 10))
+	cmd := NewIntCmd("INCRBY", key, formatInt(value))
 	c.Process(cmd)
 	return cmd
 }
@@ -450,28 +482,43 @@ func (c *commandable) IncrByFloat(key string, value float64) *FloatCmd {
 }
 
 func (c *commandable) MGet(keys ...string) *SliceCmd {
-	args := append([]string{"MGET"}, keys...)
+	args := make([]interface{}, 1+len(keys))
+	args[0] = "MGET"
+	for i, key := range keys {
+		args[1+i] = key
+	}
 	cmd := NewSliceCmd(args...)
 	c.Process(cmd)
 	return cmd
 }
 
 func (c *commandable) MSet(pairs ...string) *StatusCmd {
-	args := append([]string{"MSET"}, pairs...)
+	args := make([]interface{}, 1+len(pairs))
+	args[0] = "MSET"
+	for i, pair := range pairs {
+		args[1+i] = pair
+	}
 	cmd := NewStatusCmd(args...)
 	c.Process(cmd)
 	return cmd
 }
 
 func (c *commandable) MSetNX(pairs ...string) *BoolCmd {
-	args := append([]string{"MSETNX"}, pairs...)
+	args := make([]interface{}, 1+len(pairs))
+	args[0] = "MSETNX"
+	for i, pair := range pairs {
+		args[1+i] = pair
+	}
 	cmd := NewBoolCmd(args...)
 	c.Process(cmd)
 	return cmd
 }
 
-func (c *commandable) Set(key, value string, expiration time.Duration) *StatusCmd {
-	args := []string{"SET", key, value}
+func (c *commandable) Set(key string, value interface{}, expiration time.Duration) *StatusCmd {
+	args := make([]interface{}, 3, 5)
+	args[0] = "SET"
+	args[1] = key
+	args[2] = value
 	if expiration > 0 {
 		if usePrecise(expiration) {
 			args = append(args, "PX", formatMs(expiration))
@@ -488,14 +535,14 @@ func (c *commandable) SetBit(key string, offset int64, value int) *IntCmd {
 	cmd := NewIntCmd(
 		"SETBIT",
 		key,
-		strconv.FormatInt(offset, 10),
-		strconv.FormatInt(int64(value), 10),
+		formatInt(offset),
+		formatInt(int64(value)),
 	)
 	c.Process(cmd)
 	return cmd
 }
 
-func (c *commandable) SetNX(key, value string, expiration time.Duration) *BoolCmd {
+func (c *commandable) SetNX(key string, value interface{}, expiration time.Duration) *BoolCmd {
 	var cmd *BoolCmd
 	if expiration == 0 {
 		// Use old `SETNX` to support old Redis versions.
@@ -511,7 +558,7 @@ func (c *commandable) SetNX(key, value string, expiration time.Duration) *BoolCm
 	return cmd
 }
 
-func (c *Client) SetXX(key, value string, expiration time.Duration) *BoolCmd {
+func (c *Client) SetXX(key string, value interface{}, expiration time.Duration) *BoolCmd {
 	var cmd *BoolCmd
 	if usePrecise(expiration) {
 		cmd = NewBoolCmd("SET", key, value, "PX", formatMs(expiration), "XX")
@@ -523,7 +570,7 @@ func (c *Client) SetXX(key, value string, expiration time.Duration) *BoolCmd {
 }
 
 func (c *commandable) SetRange(key string, offset int64, value string) *IntCmd {
-	cmd := NewIntCmd("SETRANGE", key, strconv.FormatInt(offset, 10), value)
+	cmd := NewIntCmd("SETRANGE", key, formatInt(offset), value)
 	c.Process(cmd)
 	return cmd
 }
@@ -537,7 +584,12 @@ func (c *commandable) StrLen(key string) *IntCmd {
 //------------------------------------------------------------------------------
 
 func (c *commandable) HDel(key string, fields ...string) *IntCmd {
-	args := append([]string{"HDEL", key}, fields...)
+	args := make([]interface{}, 2+len(fields))
+	args[0] = "HDEL"
+	args[1] = key
+	for i, field := range fields {
+		args[2+i] = field
+	}
 	cmd := NewIntCmd(args...)
 	c.Process(cmd)
 	return cmd
@@ -568,7 +620,7 @@ func (c *commandable) HGetAllMap(key string) *StringStringMapCmd {
 }
 
 func (c *commandable) HIncrBy(key, field string, incr int64) *IntCmd {
-	cmd := NewIntCmd("HINCRBY", key, field, strconv.FormatInt(incr, 10))
+	cmd := NewIntCmd("HINCRBY", key, field, formatInt(incr))
 	c.Process(cmd)
 	return cmd
 }
@@ -592,14 +644,26 @@ func (c *commandable) HLen(key string) *IntCmd {
 }
 
 func (c *commandable) HMGet(key string, fields ...string) *SliceCmd {
-	args := append([]string{"HMGET", key}, fields...)
+	args := make([]interface{}, 2+len(fields))
+	args[0] = "HMGET"
+	args[1] = key
+	for i, field := range fields {
+		args[2+i] = field
+	}
 	cmd := NewSliceCmd(args...)
 	c.Process(cmd)
 	return cmd
 }
 
 func (c *commandable) HMSet(key, field, value string, pairs ...string) *StatusCmd {
-	args := append([]string{"HMSET", key, field, value}, pairs...)
+	args := make([]interface{}, 4+len(pairs))
+	args[0] = "HMSET"
+	args[1] = key
+	args[2] = field
+	args[3] = value
+	for i, pair := range pairs {
+		args[4+i] = pair
+	}
 	cmd := NewStatusCmd(args...)
 	c.Process(cmd)
 	return cmd
@@ -626,8 +690,12 @@ func (c *commandable) HVals(key string) *StringSliceCmd {
 //------------------------------------------------------------------------------
 
 func (c *commandable) BLPop(timeout time.Duration, keys ...string) *StringSliceCmd {
-	args := append([]string{"BLPOP"}, keys...)
-	args = append(args, formatSec(timeout))
+	args := make([]interface{}, 2+len(keys))
+	args[0] = "BLPOP"
+	for i, key := range keys {
+		args[1+i] = key
+	}
+	args[len(args)-1] = formatSec(timeout)
 	cmd := NewStringSliceCmd(args...)
 	cmd.setReadTimeout(readTimeout(timeout))
 	c.Process(cmd)
@@ -635,8 +703,12 @@ func (c *commandable) BLPop(timeout time.Duration, keys ...string) *StringSliceC
 }
 
 func (c *commandable) BRPop(timeout time.Duration, keys ...string) *StringSliceCmd {
-	args := append([]string{"BRPOP"}, keys...)
-	args = append(args, formatSec(timeout))
+	args := make([]interface{}, 2+len(keys))
+	args[0] = "BRPOP"
+	for i, key := range keys {
+		args[1+i] = key
+	}
+	args[len(args)-1] = formatSec(timeout)
 	cmd := NewStringSliceCmd(args...)
 	cmd.setReadTimeout(readTimeout(timeout))
 	c.Process(cmd)
@@ -656,7 +728,7 @@ func (c *commandable) BRPopLPush(source, destination string, timeout time.Durati
 }
 
 func (c *commandable) LIndex(key string, index int64) *StringCmd {
-	cmd := NewStringCmd("LINDEX", key, strconv.FormatInt(index, 10))
+	cmd := NewStringCmd("LINDEX", key, formatInt(index))
 	c.Process(cmd)
 	return cmd
 }
@@ -680,7 +752,12 @@ func (c *commandable) LPop(key string) *StringCmd {
 }
 
 func (c *commandable) LPush(key string, values ...string) *IntCmd {
-	args := append([]string{"LPUSH", key}, values...)
+	args := make([]interface{}, 2+len(values))
+	args[0] = "LPUSH"
+	args[1] = key
+	for i, value := range values {
+		args[2+i] = value
+	}
 	cmd := NewIntCmd(args...)
 	c.Process(cmd)
 	return cmd
@@ -696,21 +773,21 @@ func (c *commandable) LRange(key string, start, stop int64) *StringSliceCmd {
 	cmd := NewStringSliceCmd(
 		"LRANGE",
 		key,
-		strconv.FormatInt(start, 10),
-		strconv.FormatInt(stop, 10),
+		formatInt(start),
+		formatInt(stop),
 	)
 	c.Process(cmd)
 	return cmd
 }
 
 func (c *commandable) LRem(key string, count int64, value string) *IntCmd {
-	cmd := NewIntCmd("LREM", key, strconv.FormatInt(count, 10), value)
+	cmd := NewIntCmd("LREM", key, formatInt(count), value)
 	c.Process(cmd)
 	return cmd
 }
 
 func (c *commandable) LSet(key string, index int64, value string) *StatusCmd {
-	cmd := NewStatusCmd("LSET", key, strconv.FormatInt(index, 10), value)
+	cmd := NewStatusCmd("LSET", key, formatInt(index), value)
 	c.Process(cmd)
 	return cmd
 }
@@ -719,8 +796,8 @@ func (c *commandable) LTrim(key string, start, stop int64) *StatusCmd {
 	cmd := NewStatusCmd(
 		"LTRIM",
 		key,
-		strconv.FormatInt(start, 10),
-		strconv.FormatInt(stop, 10),
+		formatInt(start),
+		formatInt(stop),
 	)
 	c.Process(cmd)
 	return cmd
@@ -739,7 +816,12 @@ func (c *commandable) RPopLPush(source, destination string) *StringCmd {
 }
 
 func (c *commandable) RPush(key string, values ...string) *IntCmd {
-	args := append([]string{"RPUSH", key}, values...)
+	args := make([]interface{}, 2+len(values))
+	args[0] = "RPUSH"
+	args[1] = key
+	for i, value := range values {
+		args[2+i] = value
+	}
 	cmd := NewIntCmd(args...)
 	c.Process(cmd)
 	return cmd
@@ -754,7 +836,12 @@ func (c *commandable) RPushX(key string, value string) *IntCmd {
 //------------------------------------------------------------------------------
 
 func (c *commandable) SAdd(key string, members ...string) *IntCmd {
-	args := append([]string{"SADD", key}, members...)
+	args := make([]interface{}, 2+len(members))
+	args[0] = "SADD"
+	args[1] = key
+	for i, member := range members {
+		args[2+i] = member
+	}
 	cmd := NewIntCmd(args...)
 	c.Process(cmd)
 	return cmd
@@ -767,28 +854,46 @@ func (c *commandable) SCard(key string) *IntCmd {
 }
 
 func (c *commandable) SDiff(keys ...string) *StringSliceCmd {
-	args := append([]string{"SDIFF"}, keys...)
+	args := make([]interface{}, 1+len(keys))
+	args[0] = "SDIFF"
+	for i, key := range keys {
+		args[1+i] = key
+	}
 	cmd := NewStringSliceCmd(args...)
 	c.Process(cmd)
 	return cmd
 }
 
 func (c *commandable) SDiffStore(destination string, keys ...string) *IntCmd {
-	args := append([]string{"SDIFFSTORE", destination}, keys...)
+	args := make([]interface{}, 2+len(keys))
+	args[0] = "SDIFFSTORE"
+	args[1] = destination
+	for i, key := range keys {
+		args[2+i] = key
+	}
 	cmd := NewIntCmd(args...)
 	c.Process(cmd)
 	return cmd
 }
 
 func (c *commandable) SInter(keys ...string) *StringSliceCmd {
-	args := append([]string{"SINTER"}, keys...)
+	args := make([]interface{}, 1+len(keys))
+	args[0] = "SINTER"
+	for i, key := range keys {
+		args[1+i] = key
+	}
 	cmd := NewStringSliceCmd(args...)
 	c.Process(cmd)
 	return cmd
 }
 
 func (c *commandable) SInterStore(destination string, keys ...string) *IntCmd {
-	args := append([]string{"SINTERSTORE", destination}, keys...)
+	args := make([]interface{}, 2+len(keys))
+	args[0] = "SINTERSTORE"
+	args[1] = destination
+	for i, key := range keys {
+		args[2+i] = key
+	}
 	cmd := NewIntCmd(args...)
 	c.Process(cmd)
 	return cmd
@@ -825,21 +930,35 @@ func (c *commandable) SRandMember(key string) *StringCmd {
 }
 
 func (c *commandable) SRem(key string, members ...string) *IntCmd {
-	args := append([]string{"SREM", key}, members...)
+	args := make([]interface{}, 2+len(members))
+	args[0] = "SREM"
+	args[1] = key
+	for i, member := range members {
+		args[2+i] = member
+	}
 	cmd := NewIntCmd(args...)
 	c.Process(cmd)
 	return cmd
 }
 
 func (c *commandable) SUnion(keys ...string) *StringSliceCmd {
-	args := append([]string{"SUNION"}, keys...)
+	args := make([]interface{}, 1+len(keys))
+	args[0] = "SUNION"
+	for i, key := range keys {
+		args[1+i] = key
+	}
 	cmd := NewStringSliceCmd(args...)
 	c.Process(cmd)
 	return cmd
 }
 
 func (c *commandable) SUnionStore(destination string, keys ...string) *IntCmd {
-	args := append([]string{"SUNIONSTORE", destination}, keys...)
+	args := make([]interface{}, 2+len(keys))
+	args[0] = "SUNIONSTORE"
+	args[1] = destination
+	for i, key := range keys {
+		args[2+i] = key
+	}
 	cmd := NewIntCmd(args...)
 	c.Process(cmd)
 	return cmd
@@ -858,7 +977,7 @@ type ZStore struct {
 }
 
 func (c *commandable) ZAdd(key string, members ...Z) *IntCmd {
-	args := make([]string, 2+2*len(members))
+	args := make([]interface{}, 2+2*len(members))
 	args[0] = "ZADD"
 	args[1] = key
 	for i, m := range members {
@@ -893,12 +1012,17 @@ func (c *commandable) ZInterStore(
 	store ZStore,
 	keys ...string,
 ) *IntCmd {
-	args := []string{"ZINTERSTORE", destination, strconv.FormatInt(int64(len(keys)), 10)}
-	args = append(args, keys...)
+	args := make([]interface{}, 3+len(keys))
+	args[0] = "ZINTERSTORE"
+	args[1] = destination
+	args[2] = strconv.Itoa(len(keys))
+	for i, key := range keys {
+		args[3+i] = key
+	}
 	if len(store.Weights) > 0 {
 		args = append(args, "WEIGHTS")
 		for _, weight := range store.Weights {
-			args = append(args, strconv.FormatInt(weight, 10))
+			args = append(args, formatInt(weight))
 		}
 	}
 	if store.Aggregate != "" {
@@ -910,11 +1034,11 @@ func (c *commandable) ZInterStore(
 }
 
 func (c *commandable) zRange(key string, start, stop int64, withScores bool) *StringSliceCmd {
-	args := []string{
+	args := []interface{}{
 		"ZRANGE",
 		key,
-		strconv.FormatInt(start, 10),
-		strconv.FormatInt(stop, 10),
+		formatInt(start),
+		formatInt(stop),
 	}
 	if withScores {
 		args = append(args, "WITHSCORES")
@@ -929,11 +1053,11 @@ func (c *commandable) ZRange(key string, start, stop int64) *StringSliceCmd {
 }
 
 func (c *commandable) ZRangeWithScores(key string, start, stop int64) *ZSliceCmd {
-	args := []string{
+	args := []interface{}{
 		"ZRANGE",
 		key,
-		strconv.FormatInt(start, 10),
-		strconv.FormatInt(stop, 10),
+		formatInt(start),
+		formatInt(stop),
 		"WITHSCORES",
 	}
 	cmd := NewZSliceCmd(args...)
@@ -947,7 +1071,7 @@ type ZRangeByScore struct {
 }
 
 func (c *commandable) zRangeByScore(key string, opt ZRangeByScore, withScores bool) *StringSliceCmd {
-	args := []string{"ZRANGEBYSCORE", key, opt.Min, opt.Max}
+	args := []interface{}{"ZRANGEBYSCORE", key, opt.Min, opt.Max}
 	if withScores {
 		args = append(args, "WITHSCORES")
 	}
@@ -955,8 +1079,8 @@ func (c *commandable) zRangeByScore(key string, opt ZRangeByScore, withScores bo
 		args = append(
 			args,
 			"LIMIT",
-			strconv.FormatInt(opt.Offset, 10),
-			strconv.FormatInt(opt.Count, 10),
+			formatInt(opt.Offset),
+			formatInt(opt.Count),
 		)
 	}
 	cmd := NewStringSliceCmd(args...)
@@ -969,13 +1093,13 @@ func (c *commandable) ZRangeByScore(key string, opt ZRangeByScore) *StringSliceC
 }
 
 func (c *commandable) ZRangeByScoreWithScores(key string, opt ZRangeByScore) *ZSliceCmd {
-	args := []string{"ZRANGEBYSCORE", key, opt.Min, opt.Max, "WITHSCORES"}
+	args := []interface{}{"ZRANGEBYSCORE", key, opt.Min, opt.Max, "WITHSCORES"}
 	if opt.Offset != 0 || opt.Count != 0 {
 		args = append(
 			args,
 			"LIMIT",
-			strconv.FormatInt(opt.Offset, 10),
-			strconv.FormatInt(opt.Count, 10),
+			formatInt(opt.Offset),
+			formatInt(opt.Count),
 		)
 	}
 	cmd := NewZSliceCmd(args...)
@@ -990,7 +1114,12 @@ func (c *commandable) ZRank(key, member string) *IntCmd {
 }
 
 func (c *commandable) ZRem(key string, members ...string) *IntCmd {
-	args := append([]string{"ZREM", key}, members...)
+	args := make([]interface{}, 2+len(members))
+	args[0] = "ZREM"
+	args[1] = key
+	for i, member := range members {
+		args[2+i] = member
+	}
 	cmd := NewIntCmd(args...)
 	c.Process(cmd)
 	return cmd
@@ -1000,8 +1129,8 @@ func (c *commandable) ZRemRangeByRank(key string, start, stop int64) *IntCmd {
 	cmd := NewIntCmd(
 		"ZREMRANGEBYRANK",
 		key,
-		strconv.FormatInt(start, 10),
-		strconv.FormatInt(stop, 10),
+		formatInt(start),
+		formatInt(stop),
 	)
 	c.Process(cmd)
 	return cmd
@@ -1026,13 +1155,13 @@ func (c *commandable) ZRevRangeWithScores(key string, start, stop int64) *ZSlice
 }
 
 func (c *commandable) ZRevRangeByScore(key string, opt ZRangeByScore) *StringSliceCmd {
-	args := []string{"ZREVRANGEBYSCORE", key, opt.Max, opt.Min}
+	args := []interface{}{"ZREVRANGEBYSCORE", key, opt.Max, opt.Min}
 	if opt.Offset != 0 || opt.Count != 0 {
 		args = append(
 			args,
 			"LIMIT",
-			strconv.FormatInt(opt.Offset, 10),
-			strconv.FormatInt(opt.Count, 10),
+			formatInt(opt.Offset),
+			formatInt(opt.Count),
 		)
 	}
 	cmd := NewStringSliceCmd(args...)
@@ -1041,13 +1170,13 @@ func (c *commandable) ZRevRangeByScore(key string, opt ZRangeByScore) *StringSli
 }
 
 func (c *commandable) ZRevRangeByScoreWithScores(key string, opt ZRangeByScore) *ZSliceCmd {
-	args := []string{"ZREVRANGEBYSCORE", key, opt.Max, opt.Min, "WITHSCORES"}
+	args := []interface{}{"ZREVRANGEBYSCORE", key, opt.Max, opt.Min, "WITHSCORES"}
 	if opt.Offset != 0 || opt.Count != 0 {
 		args = append(
 			args,
 			"LIMIT",
-			strconv.FormatInt(opt.Offset, 10),
-			strconv.FormatInt(opt.Count, 10),
+			formatInt(opt.Offset),
+			formatInt(opt.Count),
 		)
 	}
 	cmd := NewZSliceCmd(args...)
@@ -1068,12 +1197,17 @@ func (c *commandable) ZScore(key, member string) *FloatCmd {
 }
 
 func (c *commandable) ZUnionStore(dest string, store ZStore, keys ...string) *IntCmd {
-	args := []string{"ZUNIONSTORE", dest, strconv.FormatInt(int64(len(keys)), 10)}
-	args = append(args, keys...)
+	args := make([]interface{}, 3+len(keys))
+	args[0] = "ZUNIONSTORE"
+	args[1] = dest
+	args[2] = strconv.Itoa(len(keys))
+	for i, key := range keys {
+		args[3+i] = key
+	}
 	if len(store.Weights) > 0 {
 		args = append(args, "WEIGHTS")
 		for _, weight := range store.Weights {
-			args = append(args, strconv.FormatInt(weight, 10))
+			args = append(args, formatInt(weight))
 		}
 	}
 	if store.Aggregate != "" {
@@ -1182,11 +1316,11 @@ func (c *commandable) Save() *StatusCmd {
 }
 
 func (c *commandable) shutdown(modifier string) *StatusCmd {
-	var args []string
+	var args []interface{}
 	if modifier == "" {
-		args = []string{"SHUTDOWN"}
+		args = []interface{}{"SHUTDOWN"}
 	} else {
-		args = []string{"SHUTDOWN", modifier}
+		args = []interface{}{"SHUTDOWN", modifier}
 	}
 	cmd := newKeylessStatusCmd(args...)
 	c.Process(cmd)
@@ -1239,9 +1373,17 @@ func (c *commandable) Time() *StringSliceCmd {
 //------------------------------------------------------------------------------
 
 func (c *commandable) Eval(script string, keys []string, args []string) *Cmd {
-	cmdArgs := []string{"EVAL", script, strconv.FormatInt(int64(len(keys)), 10)}
-	cmdArgs = append(cmdArgs, keys...)
-	cmdArgs = append(cmdArgs, args...)
+	cmdArgs := make([]interface{}, 3+len(keys)+len(args))
+	cmdArgs[0] = "EVAL"
+	cmdArgs[1] = script
+	cmdArgs[2] = strconv.Itoa(len(keys))
+	for i, key := range keys {
+		cmdArgs[3+i] = key
+	}
+	pos := 3 + len(keys)
+	for i, arg := range args {
+		cmdArgs[pos+i] = arg
+	}
 	cmd := NewCmd(cmdArgs...)
 	if len(keys) > 0 {
 		cmd._clusterKeyPos = 3
@@ -1251,9 +1393,17 @@ func (c *commandable) Eval(script string, keys []string, args []string) *Cmd {
 }
 
 func (c *commandable) EvalSha(sha1 string, keys []string, args []string) *Cmd {
-	cmdArgs := []string{"EVALSHA", sha1, strconv.FormatInt(int64(len(keys)), 10)}
-	cmdArgs = append(cmdArgs, keys...)
-	cmdArgs = append(cmdArgs, args...)
+	cmdArgs := make([]interface{}, 3+len(keys)+len(args))
+	cmdArgs[0] = "EVALSHA"
+	cmdArgs[1] = sha1
+	cmdArgs[2] = strconv.Itoa(len(keys))
+	for i, key := range keys {
+		cmdArgs[3+i] = key
+	}
+	pos := 3 + len(keys)
+	for i, arg := range args {
+		cmdArgs[pos+i] = arg
+	}
 	cmd := NewCmd(cmdArgs...)
 	if len(keys) > 0 {
 		cmd._clusterKeyPos = 3
@@ -1263,7 +1413,12 @@ func (c *commandable) EvalSha(sha1 string, keys []string, args []string) *Cmd {
 }
 
 func (c *commandable) ScriptExists(scripts ...string) *BoolSliceCmd {
-	args := append([]string{"SCRIPT", "EXISTS"}, scripts...)
+	args := make([]interface{}, 2+len(scripts))
+	args[0] = "SCRIPT"
+	args[1] = "EXISTS"
+	for i, script := range scripts {
+		args[2+i] = script
+	}
 	cmd := NewBoolSliceCmd(args...)
 	cmd._clusterKeyPos = 0
 	c.Process(cmd)
@@ -1301,7 +1456,7 @@ func (c *commandable) DebugObject(key string) *StringCmd {
 //------------------------------------------------------------------------------
 
 func (c *commandable) PubSubChannels(pattern string) *StringSliceCmd {
-	args := []string{"PUBSUB", "CHANNELS"}
+	args := []interface{}{"PUBSUB", "CHANNELS"}
 	if pattern != "*" {
 		args = append(args, pattern)
 	}
@@ -1312,8 +1467,12 @@ func (c *commandable) PubSubChannels(pattern string) *StringSliceCmd {
 }
 
 func (c *commandable) PubSubNumSub(channels ...string) *StringIntMapCmd {
-	args := []string{"PUBSUB", "NUMSUB"}
-	args = append(args, channels...)
+	args := make([]interface{}, 2+len(channels))
+	args[0] = "PUBSUB"
+	args[1] = "NUMSUB"
+	for i, channel := range channels {
+		args[2+i] = channel
+	}
 	cmd := NewStringIntMapCmd(args...)
 	cmd._clusterKeyPos = 0
 	c.Process(cmd)
@@ -1369,11 +1528,11 @@ func (c *commandable) ClusterFailover() *StatusCmd {
 }
 
 func (c *commandable) ClusterAddSlots(slots ...int) *StatusCmd {
-	args := make([]string, len(slots)+2)
+	args := make([]interface{}, 2+len(slots))
 	args[0] = "CLUSTER"
-	args[1] = "addslots"
+	args[1] = "ADDSLOTS"
 	for i, num := range slots {
-		args[i+2] = strconv.Itoa(num)
+		args[2+i] = strconv.Itoa(num)
 	}
 	cmd := newKeylessStatusCmd(args...)
 	c.Process(cmd)
diff --git a/commands_test.go b/commands_test.go
index ef593e1..0e0405e 100644
--- a/commands_test.go
+++ b/commands_test.go
@@ -1,7 +1,9 @@
 package redis_test
 
 import (
+	"encoding/json"
 	"fmt"
+	"reflect"
 	"strconv"
 	"sync"
 	"testing"
@@ -2286,4 +2288,95 @@ var _ = Describe("Commands", func() {
 
 	})
 
+	Describe("marshaling/unmarshaling", func() {
+
+		type convTest struct {
+			value  interface{}
+			wanted string
+			dest   interface{}
+		}
+
+		convTests := []convTest{
+			{nil, "", nil},
+			{"hello", "hello", new(string)},
+			{[]byte("hello"), "hello", new([]byte)},
+			{int(1), "1", new(int)},
+			{int8(1), "1", new(int8)},
+			{int16(1), "1", new(int16)},
+			{int32(1), "1", new(int32)},
+			{int64(1), "1", new(int64)},
+			{uint(1), "1", new(uint)},
+			{uint8(1), "1", new(uint8)},
+			{uint16(1), "1", new(uint16)},
+			{uint32(1), "1", new(uint32)},
+			{uint64(1), "1", new(uint64)},
+			{float32(1.0), "1", new(float32)},
+			{float64(1.0), "1", new(float64)},
+			{true, "1", new(bool)},
+			{false, "0", new(bool)},
+		}
+
+		It("should convert to string", func() {
+			for _, test := range convTests {
+				err := client.Set("key", test.value, 0).Err()
+				Expect(err).NotTo(HaveOccurred())
+
+				s, err := client.Get("key").Result()
+				Expect(err).NotTo(HaveOccurred())
+				Expect(s).To(Equal(test.wanted))
+
+				if test.dest == nil {
+					continue
+				}
+
+				err = client.Get("key").Scan(test.dest)
+				Expect(err).NotTo(HaveOccurred())
+				Expect(deref(test.dest)).To(Equal(test.value))
+			}
+		})
+
+	})
+
+	Describe("json marshaling/unmarshaling", func() {
+		BeforeEach(func() {
+			value := &numberStruct{Number: 42}
+			err := client.Set("key", value, 0).Err()
+			Expect(err).NotTo(HaveOccurred())
+		})
+
+		It("should marshal custom values using json", func() {
+			s, err := client.Get("key").Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(s).To(Equal(`{"Number":42}`))
+		})
+
+		It("should scan custom values using json", func() {
+			value := &numberStruct{}
+			err := client.Get("key").Scan(value)
+			Expect(err).To(BeNil())
+			Expect(value.Number).To(Equal(42))
+		})
+
+	})
+
 })
+
+type numberStruct struct {
+	Number int
+}
+
+func (s *numberStruct) MarshalBinary() ([]byte, error) {
+	return json.Marshal(s)
+}
+
+func (s *numberStruct) UnmarshalBinary(b []byte) error {
+	return json.Unmarshal(b, s)
+}
+
+func deref(viface interface{}) interface{} {
+	v := reflect.ValueOf(viface)
+	for v.Kind() == reflect.Ptr {
+		v = v.Elem()
+	}
+	return v.Interface()
+}
diff --git a/conn.go b/conn.go
index 72f82b0..bf104d9 100644
--- a/conn.go
+++ b/conn.go
@@ -67,7 +67,11 @@ func (cn *conn) init(opt *Options) error {
 func (cn *conn) writeCmds(cmds ...Cmder) error {
 	buf := cn.buf[:0]
 	for _, cmd := range cmds {
-		buf = appendArgs(buf, cmd.args())
+		var err error
+		buf, err = appendArgs(buf, cmd.args())
+		if err != nil {
+			return err
+		}
 	}
 
 	_, err := cn.Write(buf)
diff --git a/multi.go b/multi.go
index 9d87de9..63ecdd5 100644
--- a/multi.go
+++ b/multi.go
@@ -44,14 +44,22 @@ func (c *Multi) Close() error {
 }
 
 func (c *Multi) Watch(keys ...string) *StatusCmd {
-	args := append([]string{"WATCH"}, keys...)
+	args := make([]interface{}, 1+len(keys))
+	args[0] = "WATCH"
+	for i, key := range keys {
+		args[1+i] = key
+	}
 	cmd := NewStatusCmd(args...)
 	c.Process(cmd)
 	return cmd
 }
 
 func (c *Multi) Unwatch(keys ...string) *StatusCmd {
-	args := append([]string{"UNWATCH"}, keys...)
+	args := make([]interface{}, 1+len(keys))
+	args[0] = "UNWATCH"
+	for i, key := range keys {
+		args[1+i] = key
+	}
 	cmd := NewStatusCmd(args...)
 	c.Process(cmd)
 	return cmd
diff --git a/parser.go b/parser.go
index 5a9c79f..48fe769 100644
--- a/parser.go
+++ b/parser.go
@@ -17,18 +17,201 @@ var (
 
 //------------------------------------------------------------------------------
 
-func appendArgs(buf []byte, args []string) []byte {
-	buf = append(buf, '*')
-	buf = strconv.AppendUint(buf, uint64(len(args)), 10)
-	buf = append(buf, '\r', '\n')
-	for _, arg := range args {
-		buf = append(buf, '$')
-		buf = strconv.AppendUint(buf, uint64(len(arg)), 10)
-		buf = append(buf, '\r', '\n')
-		buf = append(buf, arg...)
-		buf = append(buf, '\r', '\n')
+// Copy of encoding.BinaryMarshaler.
+type binaryMarshaler interface {
+	MarshalBinary() (data []byte, err error)
+}
+
+// Copy of encoding.BinaryUnmarshaler.
+type binaryUnmarshaler interface {
+	UnmarshalBinary(data []byte) error
+}
+
+func appendString(b []byte, s string) []byte {
+	b = append(b, '$')
+	b = strconv.AppendUint(b, uint64(len(s)), 10)
+	b = append(b, '\r', '\n')
+	b = append(b, s...)
+	b = append(b, '\r', '\n')
+	return b
+}
+
+func appendBytes(b, bb []byte) []byte {
+	b = append(b, '$')
+	b = strconv.AppendUint(b, uint64(len(bb)), 10)
+	b = append(b, '\r', '\n')
+	b = append(b, bb...)
+	b = append(b, '\r', '\n')
+	return b
+}
+
+func appendArg(b []byte, val interface{}) ([]byte, error) {
+	switch v := val.(type) {
+	case nil:
+		b = appendString(b, "")
+	case string:
+		b = appendString(b, v)
+	case []byte:
+		b = appendBytes(b, v)
+	case int:
+		b = appendString(b, formatInt(int64(v)))
+	case int8:
+		b = appendString(b, formatInt(int64(v)))
+	case int16:
+		b = appendString(b, formatInt(int64(v)))
+	case int32:
+		b = appendString(b, formatInt(int64(v)))
+	case int64:
+		b = appendString(b, formatInt(v))
+	case uint:
+		b = appendString(b, formatUint(uint64(v)))
+	case uint8:
+		b = appendString(b, formatUint(uint64(v)))
+	case uint16:
+		b = appendString(b, formatUint(uint64(v)))
+	case uint32:
+		b = appendString(b, formatUint(uint64(v)))
+	case uint64:
+		b = appendString(b, formatUint(v))
+	case float32:
+		b = appendString(b, formatFloat(float64(v)))
+	case float64:
+		b = appendString(b, formatFloat(v))
+	case bool:
+		if v {
+			b = appendString(b, "1")
+		} else {
+			b = appendString(b, "0")
+		}
+	default:
+		if bm, ok := val.(binaryMarshaler); ok {
+			bb, err := bm.MarshalBinary()
+			if err != nil {
+				return nil, err
+			}
+			b = appendBytes(b, bb)
+		} else {
+			err := fmt.Errorf(
+				"redis: can't marshal %T (consider implementing BinaryMarshaler)", val)
+			return nil, err
+		}
+	}
+	return b, nil
+}
+
+func appendArgs(b []byte, args []interface{}) ([]byte, error) {
+	b = append(b, '*')
+	b = strconv.AppendUint(b, uint64(len(args)), 10)
+	b = append(b, '\r', '\n')
+	for _, arg := range args {
+		var err error
+		b, err = appendArg(b, arg)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return b, nil
+}
+
+func scan(b []byte, val interface{}) error {
+	switch v := val.(type) {
+	case nil:
+		return errorf("redis: Scan(nil)")
+	case *string:
+		*v = string(b)
+		return nil
+	case *[]byte:
+		*v = b
+		return nil
+	case *int:
+		var err error
+		*v, err = strconv.Atoi(string(b))
+		return err
+	case *int8:
+		n, err := strconv.ParseInt(string(b), 10, 8)
+		if err != nil {
+			return err
+		}
+		*v = int8(n)
+		return nil
+	case *int16:
+		n, err := strconv.ParseInt(string(b), 10, 16)
+		if err != nil {
+			return err
+		}
+		*v = int16(n)
+		return nil
+	case *int32:
+		n, err := strconv.ParseInt(string(b), 10, 16)
+		if err != nil {
+			return err
+		}
+		*v = int32(n)
+		return nil
+	case *int64:
+		n, err := strconv.ParseInt(string(b), 10, 64)
+		if err != nil {
+			return err
+		}
+		*v = n
+		return nil
+	case *uint:
+		n, err := strconv.ParseUint(string(b), 10, 64)
+		if err != nil {
+			return err
+		}
+		*v = uint(n)
+		return nil
+	case *uint8:
+		n, err := strconv.ParseUint(string(b), 10, 8)
+		if err != nil {
+			return err
+		}
+		*v = uint8(n)
+		return nil
+	case *uint16:
+		n, err := strconv.ParseUint(string(b), 10, 16)
+		if err != nil {
+			return err
+		}
+		*v = uint16(n)
+		return nil
+	case *uint32:
+		n, err := strconv.ParseUint(string(b), 10, 32)
+		if err != nil {
+			return err
+		}
+		*v = uint32(n)
+		return nil
+	case *uint64:
+		n, err := strconv.ParseUint(string(b), 10, 64)
+		if err != nil {
+			return err
+		}
+		*v = n
+		return nil
+	case *float32:
+		n, err := strconv.ParseFloat(string(b), 32)
+		if err != nil {
+			return err
+		}
+		*v = float32(n)
+		return err
+	case *float64:
+		var err error
+		*v, err = strconv.ParseFloat(string(b), 64)
+		return err
+	case *bool:
+		*v = len(b) == 1 && b[0] == '1'
+		return nil
+	default:
+		if bu, ok := val.(binaryUnmarshaler); ok {
+			return bu.UnmarshalBinary(b)
+		}
+		err := fmt.Errorf(
+			"redis: can't unmarshal %T (consider implementing BinaryUnmarshaler)", val)
+		return err
 	}
-	return buf
 }
 
 //------------------------------------------------------------------------------
@@ -120,7 +303,7 @@ func parseReply(rd *bufio.Reader, p multiBulkParser) (interface{}, error) {
 	case '-':
 		return nil, errorf(string(line[1:]))
 	case '+':
-		return string(line[1:]), nil
+		return line[1:], nil
 	case ':':
 		v, err := strconv.ParseInt(string(line[1:]), 10, 64)
 		if err != nil {
@@ -141,7 +324,7 @@ func parseReply(rd *bufio.Reader, p multiBulkParser) (interface{}, error) {
 		if err != nil {
 			return nil, err
 		}
-		return string(b[:replyLen]), nil
+		return b[:replyLen], nil
 	case '*':
 		if len(line) == 3 && line[1] == '-' && line[2] == '1' {
 			return nil, Nil
@@ -166,7 +349,12 @@ func parseSlice(rd *bufio.Reader, n int64) (interface{}, error) {
 		} else if err != nil {
 			return nil, err
 		} else {
-			vals = append(vals, v)
+			switch vv := v.(type) {
+			case []byte:
+				vals = append(vals, string(vv))
+			default:
+				vals = append(vals, v)
+			}
 		}
 	}
 	return vals, nil
@@ -179,11 +367,11 @@ func parseStringSlice(rd *bufio.Reader, n int64) (interface{}, error) {
 		if err != nil {
 			return nil, err
 		}
-		v, ok := viface.(string)
+		v, ok := viface.([]byte)
 		if !ok {
 			return nil, fmt.Errorf("got %T, expected string", viface)
 		}
-		vals = append(vals, v)
+		vals = append(vals, string(v))
 	}
 	return vals, nil
 }
@@ -211,7 +399,7 @@ func parseStringStringMap(rd *bufio.Reader, n int64) (interface{}, error) {
 		if err != nil {
 			return nil, err
 		}
-		key, ok := keyiface.(string)
+		key, ok := keyiface.([]byte)
 		if !ok {
 			return nil, fmt.Errorf("got %T, expected string", keyiface)
 		}
@@ -220,12 +408,12 @@ func parseStringStringMap(rd *bufio.Reader, n int64) (interface{}, error) {
 		if err != nil {
 			return nil, err
 		}
-		value, ok := valueiface.(string)
+		value, ok := valueiface.([]byte)
 		if !ok {
 			return nil, fmt.Errorf("got %T, expected string", valueiface)
 		}
 
-		m[key] = value
+		m[string(key)] = string(value)
 	}
 	return m, nil
 }
@@ -237,7 +425,7 @@ func parseStringIntMap(rd *bufio.Reader, n int64) (interface{}, error) {
 		if err != nil {
 			return nil, err
 		}
-		key, ok := keyiface.(string)
+		key, ok := keyiface.([]byte)
 		if !ok {
 			return nil, fmt.Errorf("got %T, expected string", keyiface)
 		}
@@ -248,15 +436,14 @@ func parseStringIntMap(rd *bufio.Reader, n int64) (interface{}, error) {
 		}
 		switch value := valueiface.(type) {
 		case int64:
-			m[key] = value
+			m[string(key)] = value
 		case string:
-			m[key], err = strconv.ParseInt(value, 10, 64)
+			m[string(key)], err = strconv.ParseInt(value, 10, 64)
 			if err != nil {
 				return nil, fmt.Errorf("got %v, expected number", value)
 			}
 		default:
 			return nil, fmt.Errorf("got %T, expected number or string", valueiface)
-
 		}
 	}
 	return m, nil
@@ -271,21 +458,21 @@ func parseZSlice(rd *bufio.Reader, n int64) (interface{}, error) {
 		if err != nil {
 			return nil, err
 		}
-		member, ok := memberiface.(string)
+		member, ok := memberiface.([]byte)
 		if !ok {
 			return nil, fmt.Errorf("got %T, expected string", memberiface)
 		}
-		z.Member = member
+		z.Member = string(member)
 
 		scoreiface, err := parseReply(rd, nil)
 		if err != nil {
 			return nil, err
 		}
-		scorestr, ok := scoreiface.(string)
+		scoreb, ok := scoreiface.([]byte)
 		if !ok {
 			return nil, fmt.Errorf("got %T, expected string", scoreiface)
 		}
-		score, err := strconv.ParseFloat(scorestr, 64)
+		score, err := strconv.ParseFloat(string(scoreb), 64)
 		if err != nil {
 			return nil, err
 		}
diff --git a/parser_test.go b/parser_test.go
index 1b9e158..b71305a 100644
--- a/parser_test.go
+++ b/parser_test.go
@@ -47,7 +47,7 @@ func benchmarkParseReply(b *testing.B, reply string, p multiBulkParser, wanterr
 
 func BenchmarkAppendArgs(b *testing.B) {
 	buf := make([]byte, 0, 64)
-	args := []string{"hello", "world", "foo", "bar"}
+	args := []interface{}{"hello", "world", "foo", "bar"}
 	for i := 0; i < b.N; i++ {
 		appendArgs(buf, args)
 	}
diff --git a/pubsub.go b/pubsub.go
index 86e4bf6..26fa852 100644
--- a/pubsub.go
+++ b/pubsub.go
@@ -80,11 +80,11 @@ func (c *PubSub) ReceiveTimeout(timeout time.Duration) (interface{}, error) {
 
 	reply := cmd.Val()
 
-	msgName := reply[0].(string)
-	switch msgName {
+	kind := reply[0].(string)
+	switch kind {
 	case "subscribe", "unsubscribe", "psubscribe", "punsubscribe":
 		return &Subscription{
-			Kind:    msgName,
+			Kind:    kind,
 			Channel: reply[1].(string),
 			Count:   int(reply[2].(int64)),
 		}, nil
@@ -101,7 +101,7 @@ func (c *PubSub) ReceiveTimeout(timeout time.Duration) (interface{}, error) {
 		}, nil
 	}
 
-	return nil, fmt.Errorf("redis: unsupported message name: %q", msgName)
+	return nil, fmt.Errorf("redis: unsupported pubsub notification: %q", kind)
 }
 
 func (c *PubSub) subscribe(cmd string, channels ...string) error {
@@ -110,7 +110,11 @@ func (c *PubSub) subscribe(cmd string, channels ...string) error {
 		return err
 	}
 
-	args := append([]string{cmd}, channels...)
+	args := make([]interface{}, 1+len(channels))
+	args[0] = cmd
+	for i, channel := range channels {
+		args[1+i] = channel
+	}
 	req := NewSliceCmd(args...)
 	return cn.writeCmds(req)
 }
@@ -123,21 +127,10 @@ func (c *PubSub) PSubscribe(patterns ...string) error {
 	return c.subscribe("PSUBSCRIBE", patterns...)
 }
 
-func (c *PubSub) unsubscribe(cmd string, channels ...string) error {
-	cn, err := c.conn()
-	if err != nil {
-		return err
-	}
-
-	args := append([]string{cmd}, channels...)
-	req := NewSliceCmd(args...)
-	return cn.writeCmds(req)
-}
-
 func (c *PubSub) Unsubscribe(channels ...string) error {
-	return c.unsubscribe("UNSUBSCRIBE", channels...)
+	return c.subscribe("UNSUBSCRIBE", channels...)
 }
 
 func (c *PubSub) PUnsubscribe(patterns ...string) error {
-	return c.unsubscribe("PUNSUBSCRIBE", patterns...)
+	return c.subscribe("PUNSUBSCRIBE", patterns...)
 }
diff --git a/redis_test.go b/redis_test.go
index d8c4f7a..ac5ee7c 100644
--- a/redis_test.go
+++ b/redis_test.go
@@ -192,24 +192,6 @@ func BenchmarkRedisSet(b *testing.B) {
 	})
 }
 
-func BenchmarkRedisSetBytes(b *testing.B) {
-	client := redis.NewClient(&redis.Options{
-		Addr: benchRedisAddr,
-	})
-	defer client.Close()
-	value := bytes.Repeat([]byte{'1'}, 10000)
-
-	b.ResetTimer()
-
-	b.RunParallel(func(pb *testing.PB) {
-		for pb.Next() {
-			if err := client.Set("key", string(value), 0).Err(); err != nil {
-				b.Fatal(err)
-			}
-		}
-	})
-}
-
 func BenchmarkRedisGetNil(b *testing.B) {
 	client := redis.NewClient(&redis.Options{
 		Addr: benchRedisAddr,
@@ -235,7 +217,9 @@ func BenchmarkRedisGet(b *testing.B) {
 		Addr: benchRedisAddr,
 	})
 	defer client.Close()
-	if err := client.Set("key", "hello", 0).Err(); err != nil {
+
+	value := bytes.Repeat([]byte{'1'}, 10000)
+	if err := client.Set("key", value, 0).Err(); err != nil {
 		b.Fatal(err)
 	}
 
@@ -243,9 +227,40 @@ func BenchmarkRedisGet(b *testing.B) {
 
 	b.RunParallel(func(pb *testing.PB) {
 		for pb.Next() {
-			if err := client.Get("key").Err(); err != nil {
+			s, err := client.Get("key").Result()
+			if err != nil {
 				b.Fatal(err)
 			}
+			if len(s) != 10000 {
+				panic("len(s) != 10000")
+			}
+		}
+	})
+}
+
+func BenchmarkRedisGetSetBytes(b *testing.B) {
+	client := redis.NewClient(&redis.Options{
+		Addr: benchRedisAddr,
+	})
+	defer client.Close()
+
+	src := bytes.Repeat([]byte{'1'}, 10000)
+
+	b.ResetTimer()
+
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			if err := client.Set("key", src, 0).Err(); err != nil {
+				b.Fatal(err)
+			}
+
+			dst, err := client.Get("key").Bytes()
+			if err != nil {
+				b.Fatal(err)
+			}
+			if !bytes.Equal(dst, src) {
+				panic("len(dst) != 10000")
+			}
 		}
 	})
 }