Where the monk uses Wis as one of the key stats, the Battledancer uses Charisma instead of Wis.
They're a little more dependent upon their weapons, and Perform is one of their key skills. As I recall, they do get some form of Flurry, but their unarmed attacks are not as powerful as the core Monk.
Capoira, the martial arts style upon which the Battledancer is loosely based, arose in the Carribean, designed to be a "hidden" martial art for slaves. Many of the moves were also designed to be done while shackled, and because many of its moves resemble dance moves, it could practiced in plain view of the slaveholders. As I recall, there was even a capoirist in one of the fighting games (like Mortal Combat or Tekken).