Krieg since you have the potential to deal 25 million dmg with 1 melee hit.

Death trap is insanely overpowered. Makes the game easy. I love it.

For fun, physco

depends on your play style. both use a risk/reward system, but to different extents. Gaige is all about stacks of Anarchy, that make her more powerful, but are obtained only from kills or other methods, she has a skill where the longer you avoid reloading, the more damage you deal, and her Deathtrap is Highly customizable, capable of supporting team shields, dealing high damage, or just keeping Gaige in check. Krieg on the other hand, is a pure Brawler class, with many of his skills in the middle tree, the more damage he takes, the more powerful he becomes. he can turn into a Badass Psycho, and even has a whole tree dedicated to buffs that only work when you're set on fire. he also has a mode where if you get downed, you can run around throwing sticks of dynamite at enemies. both are great classes.