Here are my quick thoughts on the various tanks and healers:

Warrior tank - Awesome, very nice dps and does a lot of damage. Very easy to use, decent aoe threat, very very good single target threat. Has stuns up the ass too. Stamina buff that stacks with other buffs.

Paladin tank - Good. Nice aoe threat, very nice aoe pull. Decent single target threat. Okay dmg output. Easy to use, buffs/auras

Druid tank - terrible aoe threat, good single target threat. health up the ass. can rez, buff, heal. decent damage output.

Shaman healer - Chain heal is great, has a HoT with a talent/glyph. Earth shield rules, riptide is great. Can cleanse, totems are very nice for melee or caster team. Self rez, very mana efficient.

Druid - heals on the run are spectacular for certain boss fights, very good healing and nice group healing. battle rez. tree form is cool looking.

priest - kinda boring healer, good group healing. spirit buff. not bad at all, just not my favorite due to my playstyle.

pally healer - i hate them. crappy party healing. very boring. i hate their style of healing. this is just my opinion, i'm sure other people like them. when i was pugging on my tank i noticed they were the worst healers.