If you can put up with the out of sync sound and somewhat worse graphics then the ps3 version is ok. atleast in regards to ME2.
I'm not sure what you've seen/heard, but sound was perfect for me on my PS3 playthroughs of ME2, and the game looked frigging great to me.
It is actually a very common problem with the ps3 version. People started to notice shortly after the first patch. The audio would become very out of sync at certain spots and would even cut conversations off mid sentence. I have seen this problem myself with my own version.
On the graphics note, as much as I love my ps3, the 360 version is far superior. Mostly due to the game being made more with it in mind.