The weekend was pretty hectic as I tried to install Longhorn Beta 1 but the effort proved futile on my VPC. The machine kept rebooting after the initial product key/info screens and although once it got as far as two hours of installation but then rebooted only to complain of Boot.ini.
The Vista was a breeze though as it installed on the first try (though I experienced a little friction through Reboots). For some reason mapping the ISO image of the Vista CTP directly to the VPC machine configuration under Virtual Server 2005 had problems. So I had to load the Daemon tools and mount the image on host system and then connect the VPC CD/DVD to the host mounted image of Vista.
I must say that this time around MS folks have done a pretty good job with the Vista installation sequence since minimal user input is required for the the compelte OS installation.