The new ones have had terrible problems. I used a vertex 3 in my SATA 3 port for two months with occasional hiccups (beachballs), but I got so sick of it I just put the old SATA 2 drive back in. No more hiccups, and the machine is just as responsive.
When faced with a choice between reliability and speed, always choose reliability.
If you look at my sig, you will see I am using a Crucial M4 with a 2011 MBP (15") with no problems at all. Not a beachball to be seen.