I need to virtualize a server, but this needs to be stable enough for production. What are the advantages/disadvantages of the different hypervisers with CentOS

ESXi (vmware)
XEN
KVM

Primarily I will be running CentOS6.4 there may or may not be a windows server. I need stability as this will be production. I will not need the equivalent of V Motion, but would like to be able to do a physical to virtual would like the capability of snapshots and to be able to backup as files on storage (I cannot do boot from SAN, but this will be SAN attached).