I prefer getting a really powerful workstation and doing virtualization from there. Example: http://natex.us/enthoo-128kit
(No affiliation with Natex, but I've bought that kit and I enjoy the overkill of 16 cores and 128gb of RAM)
(No affiliation with Natex, but I've bought that kit and I enjoy the overkill of 16 cores and 128gb of RAM)