At the moment, winning rbg is rather good in getting bars of exp quickly. I heard someone reaching level 109 in 21 hours just running rbg.

For people that have done the lvling process thousand of times during beta, I would say go for it.

These few days Blizzard has nerfed all BGs that give good exp to kingdom come. As of current stage none of the BG will give remotely good exp for the time you spend in it. Back to pve questing for leveling as running BG is simply not worth the time spent now.