I am an avid pvp'er and love to do random bgs, rated bgs and some arena. I have quit WoW for about 1 year and coming back for MoP. I will most likely do some PvE as well. I cannot decide which to roll with - Mage or Hunter. I have both at 85.
Seems to me Mage always gets more balance and tweaking, plus it is easier to play in a pvp setting. Personally, I would choose a Mage, as all the little hunter bugs and balancing has pushed me away.