Not sure about others, but in my case (10 MBP 13" w/ Vertex2 in optibay), I had occasional stalls (anywhere from 2-30 sec) until the TRIM Enabler (
http://www.groths.org/?p=308 ) showed up and I installed it (OSX Lion supports TRIM on this drive natively, it seems).
I think this is because, although sandforce drives have native garbage collection, it can sometimes happen at a very inopportune moment (like say, a 20s "pause" during critical moments of a SC2 game).