Heroes are fun and easy. DKs take a bit more skill to manouver due to zerk requirements. HB is always in demand though. Dps can be fairly equivalent between heroes and dks if gear is good. Kinda based on what you're looking for ^^
Dmg : hero>drk Grinding: drk>hero (2shot oblivion mobs early) but heroes are too easy and boring when ur on semi god mode, drk require some more skills and alot more fun and challenging