I recently upgraded a box from Vista Business to Windows 7 Ultimate SP1. It is a client in an SBS 2011 domain. It works without problem when I use it, but much of the time when it goes into or comes out of hibernation it crashes. It will sometimes prompt for a system restore; sometimes will prompt to try an automatic repair which does not work, sometimes wakes up from hibernation briefly and then reboots, and sometimes indicate that Windows did not shut down normally and give the option for a “safe mode” start up.
I always start it in normal mode and it works just fine until the next hibernation. I never had any problems with this box (Intel Core 2 – 1.86GHZ, 2 Gigs of RAM with 20 Gigs of free space on the hard drive) in the 2 years I’ve had it with Vista Business.