XPellent. So, now I'm running Microsoft Office XP (beta 2 -- even though the real thing is done now). I probably won't have much time to comment on it, other than to say I like subtle tweaks to the toolbars and right-click menus, which I saw in VisualStudio.net, and that the Language Bar (whatever that was) messed up my keyboard shortcuts until I shut it off. Scoble has some good stuff to say on FrontPage XP -- both why it's cool and why it sucks.
BTW, in case you're wondering if I'm just a glutton for punishment, the reason I install this stuff is threefold: A) I like to see how Microsoft is evolving their UI standards -- especially for their millions-of-end-user oriented products. Much of it is good (these days). They test the hell out of it and lots and lots of people will be getting use do these standards therein. B) I want to see what's new and interesting in these tools that I can take advantage of (by plugging them into mine). C) I'm a sucker for new stuff.