I'm on PC and haven't experienced a single crash, freeze or noticeable drop in framerate. :shrug:
I had problems with Fallout 3 though, and I had to clean my system and learn what not to have installed in order to be able to play it without problems, as a I still was up until NV released. I'd suggest giving your system a good clean and updating all your drivers, and working with it until you can play without issues. My problems with Fallout 3 were my end, but only because I guess the way these games are put together makes for problems, and Gamebyro... is extremely uh, temperamental. lol