Horde are gettting completely and utterly STOMPED in pvp because the utter lack of healers.
99/100 healers on Horde are dps-wannabee spec and don't care one bit about actually supporting
their team by playing their class AS INTENDED, by healing, buffing or otherwise supporting their team.
I have seen AVs with as much as 5 healers on Horde, and ONE of them actually had healing spec.
If you want to win in pvp, you roll alliance. They paladins are EVERYWHERE and they heal, buff, dispell
and most importantly - they don't die in 2 seconds from a rogue, like shamans does.
So this is a warning to all you new players seeking advice on which faction to pick.
If you are into pvp, pick alliance.