I have followed Paul's methods very carefully and he has personally advised me on problems with my OTTB. He has never 'forced' a horse down to the ground (without tying up a leg, it is pretty hard for a 5 foot 'nothing' guy to 'throw' a 600kg horse on the ground - you try it!) Nor is the horse drugged. The endorphins RELAX the horse, it is NEVER in pain and there are no bad effects during or after. It is just controversial because people don't understand what they are seeing.
His methods have completely saved my own horse, quickly and effectively... plus I am much, much safer. All I did was 'half tap' my horse twice to achieve a completely new horse who had a plethora of problems.
Having had the priviledge of his personal advice (he even called me from Japan once), I have absolute respect for ALL his methods, which is not only The Tap, but he is truely talented in all areas of training and his Love and Dedication to horses is transparent. He often gets people's back's up because his sense of humour makes 'quips' at natural horsemanship. He lives in a different world with the pressure to produce colts for racing on the track.
But without ranting on, the question is about "The TAP", and I know for a fact it can be a very very effective method.