Yeah I have only trained MMA and BushiBan Karate which is a very eclectic martial arts system based off of Bushi Do, Ban Do, Burmese Kick boxing, and some grappling, all done as an adult. As well as a bit of Wu Shu Kung Fu, and American Karate when I was young. The American Karate was home taught by my best friend and his Black belt Dad. We were on welfare and couldn't afford it so the day after each class they would come home and teach me what was taught in class the day before. So I learned all the Katas and kicks and whatnot then. The WuShu was for almost 2 years from 13-14. I loved that bit it always almost felt more like dance than hard martial arts. I did love the fluidity from it and the paring that I learned from it really benefited me when sparring against other harder styles as I was able to deflect and control their hands much better when they attempted to strike me.
I often think of just going to a boxing gym to train for a while as it is one of the things I was always interested in but never actually trained. I am sure if I did it more my punches would be much better. Boxers in general can punch much harder than most martial artist. At least in my experience.