Now that he’s retired, I think its safe to say Demetrious Johnson had the best MMA career in history. 2 weight world champion in two different world class organizations, tied for most UFC title defenses in history, created the Mouse Trap(Suplex->Arm Bar) Only person to knock out Henry Cejudo(2 weight world champ), never has popped for PED’s or anything illegal, he was never taller than a single opponent and never had a longer arm. The GOAT.