Brazilian Jiu-Jitsu is very appealing to me because it's very "realist." In a real-world fight or confrontation between 2 people, most of the time (above 90%, I think) the combatants wind up on the ground. BJJ really teaches the student how to deal with fights on the ground. If you're in a ground fight, you need to know how to control the centre of gravity as well as the numerous holds and limb locks.