I have attended one week-long session. I found it to be a hodge-podge of gestalt therapy, some zen concepts, a mixture of existential philosophy, and a sprinkle of new-age mumbo-jumbo thrown in to make it seem more mysterious. It was also a high-pressure sales job to promote additional "classes" that would ostensibly lead to even greater enlightenment.
While I say these things critically, I will also add that some people -- I would say most -- derived some benefit from the experience. It did force you to ask yourself probing questions and to confront some of the lies you tell yourself that you don't even realize you're telling.
But it was also scary in that the group leader could manipulate people into emotional corners and keep pressing them until they "broke." This was supposed to be seen as some kind of breakthrough, and it may have been cathartic, but it was certainly traumatic.
One lady simply blew up, started screaming at the presenter, and finally flung her chair away and stormed out of the hall. And nobody had done anything to her that I could see.
So it was a worthwhile experience if you want to push your personal psychic comfort zone and discover some things about yourself. But there's also a lot of claptrap and gibberish to sort through, which makes it a lot like cleaning out the stable hoping there's a pony under all the ... fertilizer.
Not a good guy.
I wonder how he developed the "trainers."