As a healer it's BH hands down for me. I like the way the abilities mesh together + building and using stacks. Leveling as a healer wasn't great as you start with a healer companion, but after picking up your dps buddies it improves.
It's hard to pick a second; I've been making and remaking alts for a few weeks and can't find one to stick with. Force casters are too easy when hybrid speced into no-cost high damage (fall asleep). Force melee, while animated well, are way too flat and dull. You could macro their abilities to a single button and just steer them around all day. Agent / Smug healing starts very slow, but if it picks up then it might be huge fun - esp. with stealth
Looking forward to that.