Well, I did use it briefly, and didn't like how it treated you like a moron with the constant popups and no easy access to the CP.

Biggest issue is that none of our current computers have the umph needed without replacing some piece of hardware, and most of my software wouldn't work without upgrading to a newer version (IF there was even a Vista compatible version).  They greatly understate the amount of RAM needed, IMO.  

They just dropped the ball in not getting drivers out for hardware, IMO (especially printers).  Things may be better for Vista now, but they're already working on dropping it (I've read because it's been such a dud in the biz world for reasons I stated earlier).  Maybe they've learned from this disaster and the next version will be better. 

I still see Vista as a bad copy of Apple's Tiger/Leopard.  They REALLY tried to make it look and act like what Macs have, and it failed big time...again, just my opinion.