Clinton is my favorite. His methods make the most sense to me - kind if like, if you have an issue, and he says "do this and this and that", you step back and go "oh - well that makes sense why didn't I think of that?". I've also seen and had the best results from his methods. John Lyons is great, too. I've met both of them and they were both very nice in person, especially John. He talked to me about my horse for almost 20 minutes.
I'm not by any means a fan of Parelli, but that's a whole other issue.
I've spent most of my life riding horses. The rest I've just wasted.