In his fights I blame the punches to the back of the head lack of experience. As he learns he's going to be an even badder m'fer. Only issue is he is older...so how long his body will last in MMA is a question. Granted Randy Coture is 40 something. But he's learned the MMA game and its rules for years now. Kimbo for the most part is a rookie.
One thing that strikes me about Kimbo though is when you see his interviews. (Not the ones from his street fights) He seems to be all there mentally, no BS, pretty straight forward and smart answers. Tank in all the interviews I have seen is nothing but a thug, yeah hes a bad ass, but not much else in the brain area. He just wants to cash his checks and go drinking. I'd give Kimbo the edge in the IQ department. But again thats just my impression as I dont know either of them. I might be totally off so who knows.