Better healer for heroics/raids?Follow

I have a 70 druid and shaman. I consider the druid my main but he's feral. I only seem to get resto garbage in kara though "just in case". My shammy has mostly elemental gear and hasnt seen the inside of kara. My guild has a shortage of healers at times. So which class is generally liked more for heroics/raids? if shammies have the edge I'd have no problem trying to gear him up. if druids are better I could just respec when its absolutely needed

I personally prefer shaman. A druid is probably better MT healer, but the Shammy can chain heal the raid. I have to HOT each person (1 hot every 1.5 sec) he can just spam the raid and is far more effective at raid heals. Add to this the Manatide, Bloodlust & totems, and I love resto Shammys.