I worked with it a little here at work for some testing. It won't run about half our software (our software is getting old though, so it's time to upgrade). There aren't a lot of drivers available for it either. That will change as manufacturers update their drivers.

Vista, in my mind, is no different from OS X now. It has the same hardware requirements (we have a Mac downstairs that has a gig of RAM and a 3D card, which is mostly all that Vista needs). It does the same thing about asking whether or not you want to allow or deny things (Macs do this if you're doing things "outside the norm"). Once the computer is all setup though, it won't ask you those questions (assuming you don't add and remove software constantly).

I personally don't like it because we'll have to upgrade all our software and I need to adjust my login scripts. Our anti-virus and contact management don't run on it. Our VPN software doesn't run on it. So right now, all our new machines continue to be purchased with XP. Once we upgrade all our software though, I won't have a problem with upgrading to Vista.