As someone who ain't good at any of this, BJJ (or the wrestling base Southnarc suggests) is the fastest way to survival and breathing room, so to speak. Being able to default to something, survive, realize you're OK, and then do something is amazing. MT, and others, just don't give you that. There's also the stay on your feet thing that comes from BJJ, while also having an answer to getting back to your feet, or having a response on the ground. The teaching/learning method is also the best. You're typically gonna have a balls out fight before you leave BJJ. You're gonna know what does and doesn't work. Your melon simply can't take that in striking.