Resto is holding up extremely well on beta, probably has the most solid mechanical design of any healer, as well as multiple different talent builds that can be used for different damage patterns/assignments.
Right now, Druids, Paladins and Holy Priests are the 3 strongest healers and are about comparable, depending on the fight. Mistweavers and Disc Priests are a very large step behind, and have pretty severe limitations. Resto Shaman are completely worthless currently and just had all of their unique utility stripped.