I really enjoy playing dominators. My main is an illusion/martial arts dom, and I have an ice/stone and a dark/energy dom at end game as well (level 50+). What I really enjoy is their versatility. Control, ranged damage, melee damage, and even some mild buffing, depending on the set.
I've tried playing controllers, but I really enjoy mixing it up with the villains I'm arresting, and I find controllers a bit passive on that regard. Though there are always exceptions, I've found controllers don't do enough "exciting" action for my tastes. My dominators can throw hard control, soft control, ranged attacks and melee, depending on what works best on the team.
But that's when I'm playing the character. Which am I happier to see when I'm on a team? Controllers! I'm always delighted to see controllers because they can buff me or debuff the opponent. They make my play more fun, which is much appreciated.
TLDR: to play, dominator. To play with, controller. YMMV.
