In my experience AV isn't a good option any longer. I played in Ruin and Nightfall and when they 'accidentally' broke the xp a while back a ton of people bailed and few came back. My queues are 15-45 minutes usually on my 70s teams. Another problem is that the matches in these battlegroups usually end in a turtle which brings the XP/hour WAY down. I enjoy them, but my time is better spent questing.