TweetI prefer BJJ myself. I spent many years either boxing or sparring in one form of stand-up or another. I am just more interested in how to handle myself on the ground. How old are you? I know for myself, when I was much younger, I fought often and never found myself on the ground so I never felt the need to learn ground skills. Nowadays, that's all I'm interested in. Muay Thai IS a great fighting skill as well. I believe that most forms of kickboxing, no matter what they say, were designed for sport though, and even though Muay Thai is much more aggressive than American kickboxing, it still seems to be primarily a sport. Whereas BJJ seems more like self-defense (as well as a sport).
Either way you can't beat private lessons. No matter what the style.