Microsoft and Novell deliver Joint Virtualization Solution

Seems one would be better off buying RHEL5 Advanced, you get supported virtualisation with Xen, including support for Windows guests, unlimited RHEL guests inheriting the subscriptions of the host (aka free clustering, GFS etc.) and live migration.

I haven't seen any authoritative list of features, but AFAICR, Hyper-V has no live migration support at present.

With an 80-core (5 16-core boxes) running a Xen cluster on RHEL5, I really don't see a need for this in our environment ...