You should give it a try again. I've been using XenServer for the last couple of years on dual socket, dual core, old-ish Xeon 5030s (my personal server, I purchased them for about $150 a piece). I run Windows Server 2003, Windows Server 2008, Windows XP, Windows 7, Debian, Ubuntu, and OpenSolaris and have not had a single crash associated with XenServer. The PV drivers for Windows makes performance a non-issue. All of the *NIX platforms have PV kernels available.
I think your information is quite outdated. For me, it just works.
Incidentally, I chose XenServer over VMWare because it worked with my RAID controller (a 3ware device that ESXi does not - and will never, according to VMware - support).