[CentOS-virt] XEN or KVM - performance/stability/security?

Hi all.

I am currently building a small test cloud based on Eucalyptus 2.0.3 and CentOS 5.8 x64. I have a choice which hypervisor to use: KVM or XEN. KVM is the default in CentOS 6 but I have read also many good things (for example PV guest machines, isolation between Dom0 and DomU) about XEN.

Key factors from my opint of view are: - stability (which one runs more smoothly on CentOS?) - performance (XEN PV/HVM(with or without pv drivers) vs KVM HVM(with or without pv drivers)) - security

Could you share your experience in these areas?

Best regards, Rafal Radecki.