I have been quite satisfied with these products, especially Virtual PC as it is free (*see comment). The guest operating system files can be moved between Virtual PC and Virtual Server, this is ideal as working with the Virtal PC rendering of the guest O/S is much easier the the Server Client access. I get the O/S running with RDP as soon as I can, then I can leave the host machine and connect the guest O/S from somewhere more comfortable, i.e. teh deck.
For testing I still need to read up on accessing peripheral devices such as Web Cams and TV tuners, but no great need for these at the moment.
The Virtual Server provides a nice summary page from the HTTP access, a screen shot follows. I only have one O/S installed as the test box is very limited.
the Virtual Server native client is a little clunky, and for "console" access, Virtual PC works better for me, the following is a screen shot of Virtual PC to provide a contrast. Note the host is a dual processor machine, and as per microsoft documentation, only 1 of the processes is used in the guess O/S.
My initial judgement of the remote client was ill-founded, and was a reflection of the hardware rather than the application. Now that I have completed the feasibility testing I invested in better, dedicated, hardware (Core 2 Quad 2.5  & 8GB DDR2  RAM) and have found the remote client experience pleasurable.
Note: Had to downloaded the x64 Virtual Server as the 32bit version is not compatible with 2003 x64, but the quest O/S (32bit) run successfully on the x64 Virtual Server.
Other related posts:
Sony Vaio X Series (VPCX117LG) Windows 7 Restore Media
Sony Vaio X Series (VPCX117LG) first impressions
Comment by adamj, on 24-Mar-2008 14:52
Virtual Server 2005 is free too these days :)