[Users] some ovirt questions

1. For ovirt, and future rhev, what's the recommended way going forward: ovirt node vs vsdm? 2. For ovirt, and future rhev, libvirt would be supported i think, what's the recommended way in terms of API going forward? libvirt API or REST API? I am not sure what's the difference between these 2. My understanding is libvirt might only be good for one physical host, and REST API would be good for the whole cluster, is this the case?