Nutanix has a "free" KVM based hypervisor that you can use if you buy their HCI platform (you can also run VMware on top if you prefer). From what I've heard i

Nutanix has a "free" KVM based hypervisor that you can use if you buy their HCI platform (you can also run VMware on top if you prefer). From what I've heard it seems that most enterprises are moving to Hyper-V because it's already included in their Microsoft agreements (server Datacenter licenses).