I was wanting to try redoing my lab environment based off a hypervisor and thought I would go with VMWare 5, however it did not take me long to find out that my hardware just is not supported for VMWare 5 or 4 so I had to scrap that idea pretty quick. I also knew of XenServer and seeing I had already used VMWare 5 and Hyper-V in the past it seemed like the best option to try next.
The XenServer hypervisor installed very quickly and easily as did the configuration of the management console. Once I had it up and running it was just a matter of installing the management console on Windows 7 and I was able to login and create a VM. The interface itself looks clean and easy to use, and reminded me of VMWare in many ways. I was easily able to figure out how to setup a server VM and installed Windows 2008 R2 as a test.
I downloaded the free license to XenServer and tried to apply it, however it kept telling me the license file was invalid. Which was odd seeing it was the only file I had received from Citrix. I decided to go back to this issue at another time however as the video card in my Dell decided to spin up the fans to full speed constantly. This turns out was due to the fact that it no longer had the software drivers installed to properly manage the system. The system I am having to use at this time is not a server, it is a workstation and the video card is designed for games, not work.
In the future I plan on purchasing a Dell server that is designed to work with VMWare 5 (and other hypervisors), and when that happens I will spend more time dealing with more extensive labs. In the mean time I have gone back to a Windows 2008 R2 installation running Hyper-V. This allows me to install the video drivers and save my ears the agony of the constant fan noise and I am still able to do all my labs with XenApp and Windows within the Hyper-V environment.
In the end, I did like what I saw of Citrix XenServer and will revisit the software in the near future. Then I will be able to tell others which one I like best, VMWare, XenServer or Hyper-V.