[ovirt-users] el6 vs el7

Hi all, I'm planning to migrate my ovirt el6 hosts to el7. Excepting that el6 will not be supported in next release of ovirt, is there a difference of performance between el7 and el6? I mean, are qemu or libvirt for example at the same level of performance/capabilities in el6 than in el7 (knowing that qemu-kvm 0.12 is still backported on el6) ? I heard that el7.1 will support live merge, if true will el6.7 support it as well or the difference between them is there?