theres no better healer in pve, each healer has its ups and downs in different fights, raid healing druids, shammys, single target healing palla's, then priests are evenly good at both, all depends what fight and what your healing, and what your style is, if someone says..."The best healer is..." then there full of crap.
personaly i love druid healers, but i also understand different fights different healers stand out, and depending on what job your doing.