Oh gosh. I love it. I really do. (Although can't compare to Vista, I never got it. Went from XP to This).
If you really do know how to use it back and forth, it is VERY useful. If not, it's a nice upgrade. My fav things on it are:
The tool(?)bar (my brain died on me, excuse me). It's usually default at the bottom. I love how everything is so organized soooo well and you can sticky-other things on it. No need to go through the start menu... So unbelievably organized/easy. And I love the snap-feature. When you drag a window to the side, it snaps to take half the screen. I abuse that feature, I really do ;)
But yes, I love the upgrade. :)