well on my relam vek'nilash the horde always win the battle grounds and all in all have a better community.  the ally doesn't near as soid a comunity as the horde.  if i where you id pick horde.  but if you have friends that picked ally like me.  then go for ally to play with your friends.  but if not id go for the horde.

It depends if ur hard core the Horde. If ur a walky talky allince also ur age matters to. Horde wins alot of the BG I've been in but allince r good pve so I can help u with 100%