Used the beta at a friends house, the RC came out a few days ago but haven't downloaded it, probably won't bother using it until I have the full thing. XP works fine at the moment and no need to go through re installing everything just yet.
From what I've looked at it seems decent (Except for paint which fails like cod5) and all the reviews / forum posts about it say it's quite fast (People saying it boots faster than xp, well that's probably cause it's freshly installed and won't have as much to load on bootup

)
The only major complaints I know about at the moment is some issues with wireless and punkbuster - But they will most likely be fixed when it's officially released and Evenbalance release proper drivers for it.
What games have to tested on it CT? I hope all the classics work and I really wanna try DX10.1 - Also what's all this about emulating XP? Probably screw up half the time -.- like someone else said on another forum: "so we put Windows in your Windows so you can BSOD while you BSOD."