Quite frankly, I'm not a fan of the trinity. (tank, heal, damage)
When I heal I feel obsessive, like I'm playing whack a mole or Tetris, just trying to plug leaks.
And when I tank I feel compulsive, and like a control freak. And have to double check everything I do. It doesn't translate into fun for me.
Damage roles are much freer to play the game the way they like. They don't actually have to follow any particular set of rules short of shoot stuff, preferably and usually the tank's target. That frees up a lot of attention to do other things, and for me, results in relaxation and enjoyment.
Guild Wars 2 claims not to have the trinity, e.g. tank, heal and damage. But what they have instead at high level is control, support and damage. That sounds strangely euphamistic like "tank heal and damage" to me. I hope it isn't, and I hope other games follow suit. The holy trinity is an outdated MMO concept.
This. I think they should get rid of the whole Trinity System and come up with their own way to do it. As for the OPs question, I usually play as a healer (was a Holy Priest in WoW) but I've switched things up and started tanking (Bounty Hunter). I love it so far. So much fun!