Making use of Linux’s Kernel-based Virtual Machine (KVM) opens up new possibilities while users can still enjoy the VirtualBox VMM itself. The KVM support is part of the mainline kernel so there is less worries with not having to use the VirtualBox kernel driver, KVM tends to support new features quite quickly, and tends to be more actively developed than VirtualBox and is embraced by a range of organizations. Early users of this backend by Cyberus customers are said to be experiencing better performance too.
Its been a while since I’ve used virtualbox, this would allow you to use the virtualbox GUI and configuration utilities, but run the VM under KVM virtualization, correct? Is there much advantage to this over using virt-manager, or the cockpit to configure your VM’s?