lots and lots and lots and lots and lots of UI things done wrong, looks so unfinished, and don't say it's a beta because considering the evolution of Vista those things haven't changed that much
Aaaand... the USB drive with the VM drive on it just decided it really wanted to be disconnected.
Win7 didn't like that very much. It seems to be booting normally now, but the screen resolution dropped itself to 800x600 afterwards (might be because I was opening the Display control panel when my USB drive dropped out).
I haven't done much with it yet (need to install the VM additions to get pointer integration and window resizing), but looks pretty slick and seems to be performing pretty well so far (considering I've only assigned the VM 512 MB of RAM).