KVM or Xen HVM - which is better for this...?

I heard OpenVZ PV (para-virtualization) runs well and with very little (<=5%) overhead inside KVM. How about inside Xen HVM - has anyone tried that?

Looking for a versatile solution that will support different kinds of PV's (OpenVM, LXC and, ideally, also Xen PV). I should think Xen HVM would be better suited to this, but have not come across any hands-on reports about running PV's inside Xen HVM...