Does anyone know of cheng hsin and it's teacher Peter Ralston. He seems to have sound principles as far as I have read. Though his stuff seems a little beyond grasp to me. Has anyone trained with him? What do you think of this art?

I've trained with him in the UK. He's a superb martial artist and teacher. Exceptionally fast and powerful, I can see why he won the World Tournament. If you get a chance to train with him, take it! You won't regret it I promise