UAC has to be disabled before installation, it will fail otherwise. The Mac OS X theme can be installed on all 32-bit editions of Windows Vista and is fully Service Pack 1 compatible.
If you run Windows Vista and like the way OS X is designed you could install Vista OS X which transforms the Windows Vista theme to that of Mac OS X.
It seems to me that they have put lots of resources into the design which probably should have gone elsewhere but that's my personal opinion. Microsoft pimped up Windows Vista quite a bit when you compare it visually to Windows XP.
