I used to really like CA until I seen him in person. In his training he says "tap, tap, tap your horse" Well, when you can hear that "tap" in person, it is a really solid smack. I don't know if it was just that day I saw him, or if he's always that way, but in my opinion he was unnecessarily harsh to a horse that was trying its guts out to figure out what the monkey with the stick wanted. Also his videos skip some of the time he spends doing things, he whacked on the horse I seen him work for nearly 3 hours before it was doing what he wanted. Even then the horse looked to me like it was reacting out of fear, rather than responding calmly because it understood.
I feel the need to defend these clinicians a little. Yes they are in it for the money, but by "mass producing" a product they make it available to the masses. I can't afford to spend $45/hour to have private lessons with a trainer, but I can save up and get a few videos on subjects I am currently having trouble with and then work out my problems on my own. Before I started watching clinician videos, I was taking advice from anyone with a horse, and it landed me in a WORLD OF TROUBLE!
I agree that it is far better to receive personalised advice from someone who knows you and your horse, but these big name guys do fill a need, especially for the backyard hobbyist. I have videos and books from many big names, and I know I'm going to be unpopular for saying this but Parelli is my favourite. It just works for me, even if its not for everyone.