Did install TG2 on Win8 (officially Windows Developers Preview) today and did a test render: Works like a charm!
I could even install other software while rendering without experiencing the sluggishness there used to be on XP or 7 (because all cores were occupied with rendering).
There are not very much tools, like the snipping tool, aboard yet so I can't show you how it looks.
If someone wants to try it too: dev.microsoft.com is where you can dl Win*. There's a caveat: It will not install as a dual boot I found out. Your other OS will be inaccessible....
Thanks Andy. Good to know.