I still have been playing with virtualization software. I read a thread called Performance Evaluation of Xen Vs. OpenVZ on Slashdot that outlined some of the pro and cons of different virtualization software solutions.
There was a lot of bantering from the different software camps about how their chosen solution was better but one post stood out:
Linux has a lot of great VM options. VMware is a great free (cost) option, and KVM has become a great option very quickly. OpenVZ and VServer are interesting light weight OS "jail" virtualizations. They each have pros and cons, depending on your requirements and apps being used.
I'm setting up my "next generation" home linux server, and looking into the virtualization options for that. Probably a bigger factor than performance is the setup and manageability. I have found Xen to be pretty primitive compared to VMWare.. setup is a pain, documentation is spotty, and support is minimal. The one advantage of Xen is that you can (and often must) do everything with it from the command-line. The GUI tools are weak at best.
I am now leaning towards using VMWare server. But, I still need to do some testing with KVM.. articles I have read about it sound very impressive. KVM paravirtualization performance is supposed to be excellent. But, I don't know about management.
This pretty much sums up what I am looking for. I am looking for a KISS (Keep It Simple Stupid) solution. I think this should be true for all potential solutions. I want to keep good documentation, friendly/helpful user community and ease of administration at the top of my selection criteria.
Scratch Xen off the List.