I agree that Horde is the best bet for those starting out. From what I hear there are more AP Horde on at any given time, and the queues are near instant. On the downside, I hear Horde complaining about losing a majority of the matches they join.
In contrast, Alliance players have to wait about 10 mins for pops and usually end up winning about 2/3 of random (non-premade) BGs joined.