The HP MiniNote is now up to 3 operating systems: Ubuntu 8.10 (with XFCE, Gnome, and KDE 4.2 RC), Windows Fundamentals for Legacy PC's, and the Windows 7 public beta. Overall, Windows 7 has certainly been the biggest surprise.
I won't go in depth into all the features (or lack of them, really) that I've encountered. They're pretty widely covered on various sites, with a good writeup from Ars Technica. Windows 7 is an incremental upgrade to Vista; it's what Vista should have been at launch. I doubt it will be worth the paid upgrade from Vista, but I think it will finally be at the point where it's not worth recommending users to go out of their way to find machines with XP on them.