I really like Buck. I've followed CA, PP, and others, but he of all of them makes the most sense. We have his 7 Clinics series. Of all the training DVDs I've seen, his are the best and one of the cheaper sets. It doesn't answer everything and isn't a substitute for experience, but it gives you solid guidelines on how to take a horse from start to finish.
I didn't get a chance to go to his clinic when he was in AZ this year, but my sister and friends all went. They had nothing but good things to say about him including my diehard PP friends. Buck even took time out to talk with my friends 6 year old son about horses at the meet and greet. Now, the boy's hero's are Iron Man, Jack Sparrow, Spiderman, and Buck.