I have trained with him. Not the full session. But what I saw was very good and I think that the majority of martial artists have a big hole that can be filled with what he teaches.
In the bad old days, you really did worry if you were going to be killed during training. Nowdays, with all the lawyers, you really can't do it like that. Peytonn's use of not only the suits, but also stuff you may think of more appropriate from a boot camp seargent really gets you to move under the stress of a bad situation.
I would reccomend his book Real Fighting before you shell out the cash for a session with him. If you like it, great. If not, you are out a lot less money.