I installed the developer preview of Windows 8 last night and everything seems to have gone on ok but not had a great deal of time to explore everything. One thing to note is that IE10 automatically tries to use hardware GPU which the NC20 doesn't have so you need to switch it to use software instead.
Onething that doesn't seem to work is putting the NC20 to 'sleep' so hibernate is the only option. The resume from Hibernate is very fast, compared with earlier OS, but I would prefer sleep to be an option too.
I've started putting some of the Windows 7 drivers on starting with the mouse, easy screen and battery - everything else seems to be working fine.
As for performance - so far, pretty good!