LI read alot of the previous posts (not all 29 pages, but most) so I hope I'm not repeating too much of previous posts.
IMO all these trainers bring something to the table, you gotta take a bit from each to use what works with the horse your training at the time - every horse is different and may require a different technique (or a mesh of a couple of different techniques) to achieve the results you want.
The only issue I have is when you go to one of the clinics and they say you HAVE to use their halter, or lead, or what have you and the technique their trying to show you won't work without their products. I had a friend go to a NH clinic and she came in with a rope halter - but that rope halter wasn't good enough, she had to buy his brand of rope halter or the methods shown won't work. So after spending a few hundred to attend the clinic she had to pay an additional amount on a brand name overpriced halter. You should be able to work with what you got.
I know all clinics aren't like, and not all 'NH' trainers are either - it's an example.