I'm not a fan of the Hammer Buster. Though, I don't really like the 'fires as fast as you can pull the trigger' guns, particularly rifles.
It would be better if it had a Crit damage bonus.
All Jakobs guns have innate, unlisted crit damage bonuses. But yeah, the Buster is still disappointing.
Invader, Madhous, Gub, Logan's Gun, and the Volcano are also pretty subpar. I'm not a fan of Thunderball Fists either. I would have said Pitchfork, but after seeing what it does to BNK-3R, I changed my mind.
"You're breaking the game, dude!" - Borderlands 2's 'Gaige', on getting too many Anarchy stacks