Hmmm I got to say I do not believe in most NH methods. I'm not really sure when common sense left the horse world. You have to understand the horse you are working with and the training methods that would work best with his/her personality.
For instance, if you tried using all NH methods on my mare, she would most likely kill you. She bolts, she kicks, and loves to plow people over. She needs a very firm hand. If you keep that firm hand with her she is an absolute angel. But as soon as you try to love her she will squish you.
But for some horses with a softer, more gentle personality those methods may work wonders. I don't believe in sticking to one particular method. You have to pick and choose what works best with the horse in front of you.
I use a rope halter when my mare is being an absolute twat. She loves to pull back, so when her regular nylon halter wont cut it, she gets the rope halter. Stops that nonsense immediately. You always start gentle but some horses, like mine, will see how far they can go. My mare has the attitude of a 5 year old, make me.