Installed it yesterday without any problems. Of course, you can't install directly from the ISO, since it's over the 2.2GB limit that VPC has. I used Alcohol 120%'s virtual drive and mounted it there, then captured this virtual drive in my virtual machine as a physical drive!
Installed in about 2 hours. Unfortunately, the Vista Beta2 VM Additions don't seem to add much functionality. Not too surprising since the VM Additions hook into the OS.