I have this student in my school who's base is kickboxing but also trains ITF TaeKwondo, and in my opinion, this mix makes him a very unpleasent sparring partner. Not only does he have the surprise element from TKD back kicks, but also unorthodox head and body movement coming in which I can't read. He reads me however perfectly. This would have never existed in a pure TKD base, nor would his kicking fluidity from any angle and any position be that great. What are your guys experience with guys doing both KB and TKD. Are they tougher to deal with than pure kickboxers?