[Users] Difference between RHEV and ovirt

Hello all, In our company we want to use either RHEV or oVirt in a production environment. After testing RHEV for 30 days we are happy with the stability and features. Can someone explain the difference between RHEV and oVirt? Are there maybe some features just available in RHEV like Windows guest drivers or someting like that? I'm not sure if I get this right, but as oVirt is the upstream of RHEV does this means that new features like hot add nic etc. are first available in oVirt and afterwards in RHEV. Does oVirt has any drawbacks compared to RHEV other than support? Thanks in advance Patrick van der Wiel