From my experience with vista, UAC is really, really stupid. It asks for you to click a little box when you want to do almost anything. Though in Linux I actually have to enter my password, the sheer number of times UAC bugs me is absolutely incredible. So yeah, I'd say that Windows Vista handles this sort of thing much, much worse than Linux.
I don't find myself doing stuff that kicks up UAC very often. Not at home anyway. At work UAC had to go pretty much right away since it's not unusual that I install drivers and stuff several times a day. It's also a bit unfortunate for UAC that it's when you first set up your computer that you'll find UAC popping up all the time, so chances are you'll get fed up with it on your first days with Vista, while if you're able to live through that period you'd probably not find it very annoying in the long run.
I like the idea in general though, and I would have left it on at home if it wasn't for the fact that it somehow causes MSVC 2005 not to access drag'n'drop files or double-clicking solution files. Don't ask me how it could possibly have that effect, but that's just too annoying for me to live with. I end up having to use the Browse dialog for everything, which is just not the way I work normally.