Xen, KVM and my use of Free Virtualization

I'm about to roll out some VMs on Xen with RHEL5.3. With RedHat's acquisition of KVM there's a question of waiting to change platforms. I don't think this is a good idea since I want to roll out these VMs next month, not next year. There will also be support from RedHat on Xen until 2014, but the main reason I don't think it will be a big deal is that in theory it's just a matter of changing kernels on the dom0 host as well as its guest paravirtualized systems. This blogger claims success with this technique. I'm going to reproduce his results myself by migrating one of my Xen VMs on RHEL to a KVM VM on Fedora and I'll post an update with the results when I do.