Shammy healer end game?

Wondering if its worth rolling?
I like the idea of the shammy, but not sure how they compared to priests/druids? I know priests are the supreme etc. But are shammies brought in for healing at all?
Thanks
I like the idea of the shammy, but not sure how they compared to priests/druids? I know priests are the supreme etc. But are shammies brought in for healing at all?
Thanks