the answer is depends
we(big we) use kvm and vmware. My slice decided to go with KVM because it comes free with the support fees for redhat. We are not using it for database just transactional servers. Oracle licensing would be the main factor on schema.
Any opinions expressed by me are mine alone, posted from my home computer, on my own time as a free American and do not reflect the opinions of any person or company that I have had professional relations with in the past 55 years. meep