Usecases with multiple users on one piece of hardware make no sense? Is there a reason (besides the previous question) you are ignoring the ability to use containers as an alternative to virtualization for all of the perks they provide?
Linux on Xen also allows you to have multiple Linuxes on the same Xen machine. This is the most functional of all and probably also the most secure of all, XSA-108 notwithstanding.
(Also, I find this all rather odd. If you want to compare Linux+Xen to OpenBSD, XSA-105 and XSA-106 much bigger deals. They allow code in a Linux container or other sandbox to break out by exploiting a Xen bug to take control of their Linux host.)