Been using it for a little over a day as my "main os" (for a little over a day) and I must say this is a real nice change from Vista. It looks a lot nicer than XP, and has some nifty (and some annoyances, but I guess it just about retraining yourself) features.
The biggest problem so far has been IE8 which does not format some web pages correctly, especially Gmail (which I use a lot).
Oh yea, moving windows to the edge of the screen may produce results you did not expect and may take some time to get used to.
Installing the Windows Live Desktop software is also a nice addition.
Still wish I was on AmigaOS though.