Haven't managed to see him in person but I have a number of friends who have and they all highly rate him.
He is pretty difficult to get to ride with nowadays - but Kathleen Lindley, who trained with him, is touring in the UK shortly and she's worth looking up....
Another fan of his books. I think he was the first natural horseman to start talking about the concept of passive leadership, which I am a great fan of over being the alpha.
I really like his books. I'm really rather negative of anyone that claims 'natural horsemanship' or other similar ways, so wasn't sure I would think much of him as I worried he would be of the same ilk and (esp given recent threads on here!) wasn't sure I could get on board with it. But I really like! Good sense, not over fluffy or bullying and not promising magical cures with too much ego - v good books!
I'm reading Horses Never Lie at the moment and am having lots of lightbulb moments. I'm quietly impressed with his reasonings/suggestions. Have also tried a couple of things with my TB and had positive results.
He really talks sense. I have read several of his books. As the owner of a very intelligent Iberian who likes to throw his weight around but doesn't react well to confrontation, his books have really helped me. My horse's previous owners had, I think, done more harm than good by getting him to do parelli and I inherited a very confused horse - reading Mark Rashid has helped me to regain his confidence and develop his trust in me.
I also really like Perry Wood and Michael Peace, many of their techniques have helped me.
I reall enjoyed a Good Horse is Never a Bad Colour and must read his others, I've only heard good things said about him which is unusual for such peeps!!