I trained with Ruthless a couple times years ago when I had under 2 years in MMA. He beat the crap out of me. Didn't matter if it was your first day or you were a seasoned vet, he trained the same with everybody, and really tried to showcase his alpha male by bullying everybody in the gym. So I'd go with Filthy because he has never beat me up.
Filthy trained with my son at his gym for a week and gave me a kick ass autograph and picture , so I'm goin filthy .