"10. Big Vendor Support - VMware, Citrix, Red Hat and Ubuntu are your big commercial vendors using Linux for their virtualization technology. Why do they use it? Various reasons but the top reason is performance.
"9. Price - Yes, I know I'm beating a dead horse here but you have to admit that it's a big selling point. Cheap is better than expensive and free is better than cheap any way you slice it. In today's slimmer budgets, it's a significant factor in making choice"
