Considering Luke Jermay and Kenton Knepper don't use the majority of their published material in their own payed shows, I would have to strongly disagree with you. And considering your a comedy magician, I wonder how much of an advanced mentalist you really are.
I've heard from several respected mentalists/creators who have seen Jermay's live shows and have told me that they haven't seen him perform anything from his dvds. books, etc. Supposedly none of it was suggestion based and most of it was basic mentalism using basic mentalist principles.
Most good mentalists regard Jermay and Knepper as something of a joke. How much of Knepper's material do you actually own. I've had enough of his material to know that it was a waste of money.
I hate to say it, but the majority wins. There are far more unfavorable opinions of Knepper and Jermay in the mentalism world than there are favorable. There is a reason for this....
I am a comedy magician, however, I also do psychic entertainment as well as comedy mentalism. When requested, I do also do mentalism shows, but I leave most of those principles for larger promotional stunts, or larger presentations, such as a grand finale at one of my shows.
I will agree that some big names in mentalism don't have any respect for Luke or Kenton. But you also have to think that both Derren Brown, and Banachek are big fans of his. Banachek is very proud of the work Luke is doing, and defends him constantly. And both Luke and Banachek have drawn from Kenton.
From what I've seen, the majority of people who bash the two of them, are simply older elitist mentalists, who have never tried the methods, and simply discard them because they think they are impossible. For Luke, a lot of this has to do with his age.
As for the material, I own pretty much all of it. I must admit, I use much more of Luke's material though. There are some products of Kenton's that I use on a continue basis though, like Kollosal Killer (which is a very wonderful effect that many top mentalist use). I use quite a few of Luke's methods though.
And you're right, there is a reason for those unfavorable opinions. Many of them are from elitist mentalists who simply won't give them a chance because they are going into something new. Some of those opinions are because of their age (Luke's age). Others are because they couldn't perform the effects straight off, and then deemed them unworkable. Others simply because they seen the method and thought it impossible. But I think the opinions of Banachek, and Derren Brown far out weight the two.
Also, Luke even went as far to record the methods of some of his effects. And I have to say, I can attest to the fact that they work, as those effects are used through my shows at different times.