It's Vista... with a new taskbar and lots of tweaks. Thus the .1 bump in version number rather than a major revision. The new taskbar annoys me because of how it is difficult to tell which apps are running and which aren't. The little borders around running apps simply aren't enough when just glancing. I actually would almost prefer a similar little X on on the button somewhere to allow you to close it with a single click... the X's presence would also indicate the app is running and not currently just a shortcut.
Otherwise, just browing around, it's the same as Vista. The network Control Panel is just as horrible as it is in Vista. And except for minor performance tweaks, it is still as slow as Vista.
If they don't provide a free update to Vista Ultimate customers, i will be seriously disappointed.