Ellay I pve with a warrior, hunter, shaman, paladin and Druid. They are my only level 90s. I was healing on the paladin but The lack of mobility was tough for me on some heroic fights, and I never much liked the Druid tank. So, I was left to decide who I wanted to heal, and who I wanted to tank. I finally decided on Paladin tanking and Druid healing. I would like the shaman healing but it boiled down to the shaman, for me, was better off dpsing than the Druid would have been. Surprisingly though, the Druid isn't a bad 5 man pve healer. With my teams off heals from the paladin and shaman, the Druids hots keep me up better than the paladin did.

So, for shaman heals vs Druid heals I think it's situational. The shaman is probably better, but 5.2 it might change since Druid is being buffed across the board http://i.wow.joystiq.com/2013/01/15/...-15-bonuses-o/