Mickey Mantle was a great right handed hitter.

See: Monday, April 15, 2013 Switch Hitter righty/lefty splits.

I found thirteen batters when I ran this query for top switch hitters at baseball-reference.com:

Entire Careers, From 1901 to 2013, Switch-hitter, (requiring onbase_plus_slugging>=.8 and At least 7500 plate appearances), sorted by greatest On-Base Plus Slugging:

Here are the top three found:
Mickey Mantle .977

Lance Berkman .954 Chipper Jones .930

I just ran the same query for all batters.  The top three switch hitters are in the top 25 of the 157 batters found.

Mantle 10
Berkman 17 (natural lefty)
Jones 25

Next switch hitter among the 157: Bernie Williams .858 at number 65.

Thirteen of the 157 are switch hitters, 8.3%.

Monday, February 11, 2013
Batters: Lefty v. Righty "Plate Appearances"

        Righty    Lefty    Both
Min 51.34% 27.07% 2.57%
Max 63.71% 39.47% 19.99%
Ave 57.75% 33.16% 9.09%
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While switch hitters have about 9.1% of plate appearances they are only about 8.3% of the top batters.  The percent of switch hitters from 2000 through 2012 is higher, ranging from 13.6% in 2012 to 16.5% in 2004.  Carlos Beltran is the only active player among the top switch hitters, number 5 at .855, number 71 overall.

Mickey Mantle is really the only great switch hitter and that seems to be because he was a really great righty batter.  Here is a list of 21 righty batters, both switch hitters and righty only, against lefty pitchers since 1950 sorted by OPS.

From 1950 to 2013, vs LHP as RHB (within Platoon Splits), (requiring PA≥3225), sorted by greatest On-Base Plus Slugging for this split

Rk	I	Player	Split	From	To	G	OPS	GS	PA	AB	R	H	2B	3B	HR	RBI	SB	CS	BB	SO	BA	OBP	SLG	OPS	TB	GDP	HBP	SH	SF	IBB	ROE	BAbip
1	I	Hank Aaron	vs LHP as RHB	1954	1976	1366	1.007		3546	3044		967	174	23	216	582	25	10	457	282	.318	.405	.603	1.007	1835	72	10	2	33	101	41	.291
2	I	Willie Mays	vs LHP as RHB	1951	1973	1279	1.003		3509	2933		895	144	43	205	519	74	32	528	398	.305	.410	.593	1.003	1740	81	14	5	29	77	43	.292
3	I	Mickey Mantle	vs LHP as RHB	1951	1968	1196	.999		3225	2747		906	134	28	161	486	28	10	458	441	.330	.424	.575	.999	1579	66	2	3	15	51	49	.345
4		Frank Robinson	vs LHP as RHB	1956	1976	1464	.947		3936	3268		963	180	22	194	550	58	21	589	495	.295	.406	.541	.947	1769	90	45	4	30	114	51	.295
5		Al Kaline	vs LHP as RHB	1953	1974	1345	.908		3491	3001		930	161	25	129	438	19	13	444	280	.310	.398	.509	.908	1528	87	15	5	26	67	52	.306
6	I	Dave Winfield	vs LHP as RHB	1973	1995	1569	.903		4001	3454		1011	175	32	183	590	36	31	512	445	.293	.382	.521	.903	1799	118	4	2	29	102	48	.290
7		Rickey Henderson	vs LHP as RHB	1979	2003	1483	.871		4153	3384		976	181	19	117	342	410	135	721	508	.288	.414	.457	.871	1546	44	20	10	18	37	40	.309
8		Paul Molitor	vs LHP as RHB	1978	1998	1237	.870		3358	2951		951	182	28	75	333	164	53	342	291	.322	.391	.479	.870	1414	35	12	17	34	42	42	.334
9	I	Tony Perez	vs LHP as RHB	1964	1986	1378	.859		3429	3054		894	190	28	127	526	10	10	339	495	.293	.361	.498	.859	1521	74	3	3	30	64	46	.312
10		Brian Downing	vs LHP as RHB	1973	1992	1260	.845		3264	2700		755	131	5	107	382	15	14	501	407	.280	.395	.451	.845	1217	68	27	12	24	40	26	.293
11		Cal Ripken	vs LHP as RHB	1981	2001	1500	.822		3675	3261		929	192	11	128	444	9	16	357	304	.285	.354	.468	.822	1527	94	14	4	39	54	46	.279
12		Lou Piniella	vs LHP as RHB	1968	1984	1188	.809		3225	2962		928	172	22	63	382	14	19	217	250	.313	.359	.450	.809	1333	106	9	12	25	61	47	.323
13		Alan Trammell	vs LHP as RHB	1977	1996	1264	.805		3292	2881		844	160	21	73	339	71	42	335	235	.293	.366	.439	.805	1265	55	10	42	24	32	47	.297
14		Willie Randolph	vs LHP as RHB	1975	1992	1293	.786		3653	3080		914	141	30	30	272	83	39	503	207	.297	.395	.391	.786	1205	76	9	40	21	26	56	.309
15		Eddie Murray	vs LHP as RHB	1977	1997	1693	.785		4133	3708		1022	185	8	142	576	41	12	375	442	.276	.340	.445	.785	1649	122	9	0	41	59	46	.278
16		Robin Yount	vs LHP as RHB	1974	1993	1343	.783		3520	3116		890	168	37	68	375	49	40	341	372	.286	.354	.429	.783	1336	64	7	23	33	53	60	.303
17		Ted Simmons	vs LHP as RHB	1968	1988	1381	.782		3481	3123		878	156	13	102	516	4	14	303	298	.281	.345	.437	.782	1366	123	17	6	32	75	53	.282
18		Brooks Robinson	vs LHP as RHB	1955	1977	1382	.752		3462	3115		869	148	20	80	400	5	4	277	267	.279	.336	.416	.752	1297	89	12	15	43	59	47	.281
19		Dave Concepcion	vs LHP as RHB	1970	1988	1309	.746		3240	2910		833	167	14	43	300	113	43	287	344	.286	.348	.398	.746	1157	95	4	13	26	42	55	.310
20	I	Pete Rose	vs LHP as RHB	1963	1986	1689	.736		4410	3995		1171	180	31	41	376	66	36	356	297	.293	.351	.384	.736	1536	99	13	24	19	55	73	.307
21		Ozzie Smith	vs LHP as RHB	1978	1996	1470	.681		3596	3114		799	173	17	23	265	158	51	374	222	.257	.336	.345	.681	1075	59	11	70	27	23	49	.268

Provided by Baseball-Reference.com: View Play Index Tool Used
Generated 4/19/2013.

Despite the disadvantage of playing his home games in the original Yankee Stadium, which was very tough on righty batters, Mantle is in a virtual tie at the top with Aaron and Mays.  There are four other switch hitters: Murray (15), Simmons (17), Rose (20), Smith (21).