Well, my knowledge is a bit limited, but I'll tell you what I know. I'm using the 346 drivers and I haven't noticed a lot of crashing. However, it can be a bit glitchy in certain games. For instance, G-sync makes Fistful of Frags act kind of strangely: the reticle doesn't smoothly expand and contract, just two frames. It also locks up if I attempt to access the options menu. I think there's a couple other tiny things a another game but I can't think of it. I don't use it often though. It's helpful if you have games that get a lot of tearing without V-sync. However, at higher refresh rates (e.g. 120/144hz) I've found there's less tearing and V-sync has less input lag when used.

So all in all it's works well for the most part, but don't be surprised if a few games don't like it. If you're not that committed to the bleeding edge and you're not too miffed about possibly needing V-sync, I'd definitely settle on a 120/144hz monitor with a good resolution, as it'll probably be less costly. :)