Running it on an AMD C60 netbook and quite responsive. Trackpad/mouse isn't as good an experience as touch, but not bad either. One big potential problem for Windows 8 is the jarring switch between Metro and desktop. I wish type-searching for an application in desktop mode did not toss you to Metro mode. Also touch searching should not require the user to know what kind of app (Program vs. Control Panel).
Relatively minor annoyances aside, I like the OS, and I will be getting an x64 tablet when available. I'd have that Samsung now, but I expect a few hardware improvements and features for Windows 8 final.