Leveling 5x druids myself, currently level 75
ive done almost every instance so far with main as resto and rest 4x bear tanks, dps so far isnt that much less than cats, instances running nice and smooth with 4 bears

Ive spent most of 70-75 doing av and its been extremely fun with 5 ferals
Not sure how they will be in cata instances, dont think its going to go well.