boomkin right now is the most fun i've ever had in this bracket, honestly. the mobility, burst, utility, and spread pressure are hard to match. like phron mentioned, it likely takes more skill to master and see all the benefits from, but very versatile and fun to play.
resto sham is strong - a healer with flexibility in play style; utility buttons as well as strong damage, but not as fun or impactful as a boomkin imo.