Fisto wins for me.
Fisto is a bad guy gone good in most storylines for MotU.
It takes much more strength of character and a sense of endurance and "stickin' to it", than just being evil all by itself.
It's easy to be evil.
So how does that weigh in a fist-a-cuffs?
Fisto's got more fight in him I figure, he's got bigger things to fight over than just his own personal reasons.
Jitsu is just a bad guy, mind you a really awesome bad guy, that holds his own very well against Fisto I'm sure, but again, it's too easy to be bad. Therefore, Fisto edges out on top.