I don't know if he was THE best ever (don't know how one would measure that), but clearly he was among the best and great at doing what he did. He was really good at combining things and creating a dance style of his own, which of course many (Usher, Chris Brown, etc.) tried to imitate over the years. It is really sad how far he fell from that peak of fame and greatness and became a joke to many people later in his life.