I've been using Vista Business for a couple of months - its fine, fast on a good Sony Viao, and clean - but Windows Explorer does hang up if you add files to it while its running.
Those good people at Redmond have a fix straight from the 1980s in running some DOS code from the Start prompt: http://support.microsoft.com/kb/929833
Disgusting, isn't it? Beta-bloatware and not even a proper idiot (i.e. me)-proof fix. Damn their eyes!