One common question that arises is how do I choose between these 2 products
Here is a quick table that compares both the products.
Need to run one or two VMs
Good to use
More than two VM's simultaneously
Good to use
More than 4 VM's
Drag and Drop
Shared Folder between host and guest
Good to share files
Shared Networking between guest and host
Not present, can be configured through ICS.
Present and works well.
Ease of use
Not easy enough, VMRC Plus is a good option
Very easy and simple
Single VM mode
Networking between VM's
Present, can configure everything
Remote viewing of VM's
Present (VMRC client)
Not present, can be configured through mstsc
SCSI Support for the guest
Present, recommended if present on host
Support for DHCP for guest on Internal Network
Resource Allocation for Virtual Machines
Present and very fine grained
Present, but only very minimal options.
* Evaluate other criteria's
The important thing the note is that VHD and VMC are compatible across Virtual Server and Virtual PC. So if you try one out and are not satisfied you can always move to the other one.
The table is a quick reference that I use, it is not intended to be complete. For technical completeness refer the official documentation from microsoft.com.