I got my green belt in Kenpo and my Blue in Taekwondo. Of the 2, I preferred Kenpo. I've competed against Black belts both 2nd and 3rd degree in Taekwondo, full contact, and won the majority of my matches. Though I was put in severe pain for quite some time by a 4th degree. In short what degree or color belt you have means little when street fighting. MMA is probably the way to go. That is a mixture rather than a pure art.