Tried Hyper-V server
And I found managing it to be kind of a pain in a non-domain joined scenario. It installed effortlessly but when I tried to manage it using the tools from another non-domain joined workstation, it proved to be a bit problematic. There was some documentation for resolving the issues but eventually, I spent enough time figuring it out that I went back to XenServer. Though with Windows Server (I tried WinSvr8), I used the Hyper-V role and really liked it so I'm assuming that if you get passed the issues that were frustrating for me, that the free Hyper-V server would work pretty well.