Best Fallout game so far.
Iron sights is a huge improvement from the last game. Less underground annoyance and a more interesting main story. You get to make more choices in New Vegas than Fallout 3, which I think is a very good thing.
It is also a highly moddable game, though any mods added do seem to add to the crash to desktop factor. It's a really good game but has too many bugs for me to give it a perfect score.
There is a few other things that irks me, like you still being a floating pair of arms instead of having a body in first person mode and the sight being somewhat off (though there are mods to fix the last one).