I've spouted off about it but with good reason, it just didn't work for me when I first got it. However, since the service pack its a joy to use... my only quibble now is that I can't play Age of Empires or Freelancer online because of a directplay issue.
The company I work for has 6000 employees spread over about 150 offices, we are all using XP (SP2) and Office 2K3... We also have a fair bit of older hardware knocking around... for us to upgrade all of our machines to Vista would cost and absolute fortune, and in this current economic climate I really can't see us forking out anytime soon.
Also I think there are a lot of people here that would struggle with vista simply because they aren't used to it, productivity would go through the floor if we rolled it out too quickly.