I've not heard of Julie Goodnight and know very little about Chris Cox or Craig Cameron, but I have seen Clinton Anderson in person and in fact, will be going to one of his tours next weekend. I use a lot of his techniques on my horses, but I don't agree with everything he does.
The one thing I that turns me off about most of these trainers is how they only seem interested in pushing their products on you. I received free tickets to his tour and am going purely for the entertainment and hopefully to see him ride bridleless.
Stella - sweet, timid, elegant, lovely, lively, amazing
Luna - large, unattractive, naughty, adored