I played a bard on live played to end game, boxed a shammy which had nice hot's... But here I am not sure what to Duo with, a cleric or a shammy, what are peoples opinions on this?
Shaman will be significantly better right when you get slumber and canni5 AA.
But
Once you hit around Raid Tier7 -- Cleric will outmatch the shaman in almost all categories. -- But shaman will still be a solid choice at the high-endgame.
So I suggest you go with shaman -- unless you plan to stick around for a while here and have some burning need to be as good as possible at the top-end game.