The most exciting application on the virtual pc side is Xen. It is using a new approach to virtualization where they recompile an operating systems kernel to adapt for a virtual environment. Since the newer VMware license (since 3.2) doesn't allow publication of comparative benchmarks, the comparisons on this page are a little old.
So far, only open source products have been able to use this technology but that doesn't preclude Microsoft and Apple from compiling their kernel against the xen libraries. One of the best parts about Xen is that it is open source :) and community driven. If you want support look to http://www.xensource.com/
Now for the Windows options:
I found this fantastic blog from Mike Holdorf's Blog post comparing Microsoft's Virtual PC and VMware.
So after all of this, it was time to give VMWare a try. I used VMWare a long time ago and it wasn't a pleasant experience. I downloaded Workstation 5.5, installed and everything was fine. Upon download, I also downloaded a Virtual Machine Importer tool so I could reuse my existing VPC machines. I ran the importer and pulled in one of my BizTalk 2006 Beta 2 machines. Holy crap...the VMWare machine was just as fast as my host machine...something I never experienced with VPC. I think I've been sold on VMWare and here are a few of the benefits:
- Faster performance - I've been able to load Windows 2003 and XP with no issues
- Display support is better
- USB support is included
- Faster pause or hibernation - you can pause a machine with the click of a button and it's paused
- Faster start up when paused
- No more loud beeps when you do something wrong - anyone have this issue with VMRC?
- Better disk allocation - VMWare can be set up to use 2 Gig Files automatically which will lead to less fragmentation
- Did I mention faster performance?
Here is a professional comparison between the two products. For me, I like VMware because it can be run on a Linux host.
Microsoft Certified Professional Magazine Online | Print: A Virtual Shootout