I love my Hyper-V!
Recently reformatted my desktop to Windows 2008 Enterprise 64-bit (use to run Vista 32-bit) and activated Hyper-V RC.
I have tested two of my favorite EPM VPC (Core EPM 2007 demo VPC and my Development VPC) and so far it just rocks. Such an improvement compare to Virtual PC on Vista!
I have only scratched the surface of what Hyper-V can do, but basic things like compressing a disk took a fraction of the time it took on the same machine with Virtual PC.
More info on Hyper-V can be found here:
Another trick I learned, instead of accessing the VPC doing a remote desktop connection onto the server (my VPC is not connected to the network) is to use the remote management console for Vista for instance, check this blog post from Nicola Delfino for a step by step procedure.