Those two options that you list will give you very different user experiences. I suspect your satisfaction with the results will have more to do with how you intend to use the machine after you accomplish your virtualization.
If you intend to use the workstation as an interactive computer that you sit in front of, perhaps with a couple of monitors, you're going to want a hosted virtualization platform, of which VirtualBox is a good example.
If, however, you're going to put the machine in a closet and forget about it, never interacting with it directly, you'll probably be happy with a bare-metal hypervisor, of which Hyper-V Server is a good example.
Performance, in either case, is going to be mostly dependent on making sure you have the right paravirtualized drivers installed in your guest OSes and you have sufficient storage IOPS to serve all those OSes.