Pros and cons of the healing classes?

I usually play tank, but I've been wanting to get into healing as well (what can I say, I'm a sucker for support roles :D). I'm mostly a a PvE player, and would mostly be doing world bosses, flashpoint, and ops. What are the pros and cons of all the healer disciplines? Is one better at AoE heals vs single target heals? I appreciate your help in advance. :)