I am still using VMWare for some of my virtual machines – not because it’s faster… Just because the one feature that VirtualPC just doesn’t offer: USB Passthrough.
The other thing about VMWare is the number of great tools that are available. For example this one which is coming up soon:
“VMware Converter is a highly robust and scalable enterprise-class migration tool that reduces the time that IT managers spend converting physical machines to VMware virtual machines. Using a snapshot based cloning mechanism that is extremely fast and reliable, VMware Converter enables remote conversions without disrupting the source server during the conversion process.”