Your mileage may vary when it comes to bugs. I think that the Playstation 3 version is probably the buggiest. Because I play it on the Playstation 3 most of the time, and it occasionally crashes. Not as often as it used to (I got it on the release date, and my first freeze that required a hard-reset was after about three or four hours, and I'd get them every three or four hours or so), but I've been still getting them now and then. The framerate occasionally slows to an unplayable degree, requiring a reset. Especially in some of the densely populated areas. Although my current playthrough has been going on for 86 hours (and counting), and the save file is 13MB so that might be something to do with it.
I will say, however, that the PS3 version of New Vegas is a vast, vast improvement on the DLC for Fallout 3, which crashed constantly.
On the PC, I've had some CTDs, but then my gaming PC technically doesn't meet the minimum requirements and I have to run it at 640x400. The PC is obviously harder to judge as far as crashes and bugs go - some people claim to have never suffered a single crash, whereas others crash constantly.
The crashes and occasional bugs and glitches can be annoying at times (and some of the bugs can be somewhat horrifying, like the spinning head thing that I got earlier today), but I still think it's worth it. But I would say that because I personally think it's the best game released in the past five or six years.