We use cockpit at work. It’s OK, but it definitely feels limited compared to Proxmox or Xen Orchestra.
Red Hat’s focus is really on Openstack, but that’s more of a cloud virtualization platform, so not all that well suited for home use. It’s a shame because I really like Cockpit as a platform. It just needs a little love in terms of things like the graphical console and editing virtual machine resources.
My understanding is that for proper cluster management you slap Pacemaker on there.