I also run a 4xDK + 1xPally group and 5xPally (Prot) group and have to say the DK & Pally groups put out considerably more DPS than the Druids. I would expect this to be the same with a DH group. But, during longer fights I feel the Druids are considerably more survivable.

I don't have a DH group yet, its on the cards.