I'm LOVING Office 12, especially Microsoft Access (long time fan, have used since Access 1.0 -- no, really). And things are running pretty darn solid. I wouldn't necessarily recommend this to the faint of heart, but I'm not being blocked from accomplishing any work -- and in a couple of ways I can already see how productivity will get a boost with the combination of Windows Vista + Office 12.
I don't mean to sound like a PR person here -- we still do have a significant amount of work left to accomplish -- but things are *definitely* coming together.
Heck, I might just go nuts tonight and install Adobe Creative Suite (v1) to see what happens.
Update: I just showed my wife Microsoft Word 12. Her comment right off the bat: 'It looks like space, the final frontier'. That really cracked me up (and made me think we are *really* on the right track).
Update 2: Adobe Photoshop runs like a champ without skipping a beat.