What they said. A good bg weekend can make all the difference. I leveled my ally shammys from 72-80 in one EOTS weekend. Did about 2 to3 levels by just normal group queuing, then a few guys wanted to do a full premade. Once those were going, I was seeing some insane XP/hr. I did 78-79 in 63 minutes. This was with a significant amount of time waiting between queues for everybody to be ready.

Oh and yes - this was on bloodlust. If you're ally, you'll have nearly instant queues.