Hey guys I recently switched one of my servers (Dual P2.8ghz) 2GB RAM to Virtuozzo running CentOS4.4 and wow it has made a difference. I am now able to run multiple servers (though they still are a little gimped, control wise). Most of the limitations can be removed and you can find out how to do that on the SW forums.
I wanted to post my glowing review since no one has posted here in quite some time. When I first started researching virtualization I came here, and was surprised by the lack of activity in this forum area. I love it so much I plan on switching one of my Windows boxes over. I will update when it happens, since the server will be running (2 Domain controllers, 1 Exchange Server, 1 WSUS Server). The box is currently a domain controller with exchange installed.
-Chuck