Melee dps, heals & temporary health for you and the team, damage resistance and health later on. Perfect for frontline horde clearing and taking out specials at close range.
Primary: AA12 for burst damage on hard to reach enemies
Secondary: Fire Axe or Hatchet early on for rapid tall boy and bruiser take downs (depending on how good you are with hitting the weakspot to stagger), then Hatchet late game once you get Mean Drunk.
I prefer Hatchet because it's fast attack speed and low stamina cost means you can hold attack while crouched, with hellfire you're still moving at a decent speed, and can effectively mow the horde down.
This works great on Veteran and can carry a whole team if they just focus on taking out the ranged specials and exploders.
I haven't tried it on Nightmare yet.