Installed Vista to play a bit.
The huge (2 Gb!) install DVD didn't have support for my graphics card (NVidia FX 5900), my sound card (Audigy 2), or my onboard NIC (3 COM). However I had Vista drivers for the video and the XP drivers worked for the NIC and the Audigy 2.
The new 'look' is ok and one thing it does is to scale different windows. So, the installer windows actually have readable font sizes without changing the default sizes.
Not real impressed with the transparent look to the windows, but I guess it's ok.
IE 7 does some things well but it is certainly not finished. For example while you can 'open in new tab' from a URL on a page, you can't do that from 'Favorites'.
Didn't get to the bottom of it, but some apps I have want to unpack a rarfx then run from there. Several of them failed, the files were simply not in the temp directory, in fact the temp path was not there when I looked. If I unpacked manually all was well.
My Documents has been renamed Documents, My Music is Music, you get the idea. There are 'Virtual Folders' but no documentation on them. Didn't seem to work during my short stay.
Finally, the deal breaker to me was that MC 11 would install and run fine but the Direct-X Host plugin is broken. I can install it, I can open it, but the Insert DX Plugin or Chain window only shows the tiny little 'x's with no plugin info.
Most apps I tried installed and ran, but were affected in some way.
Just thought I'd save someone the effort...