I trained 2 clients last fall who were very insistent that they wanted to do that plan. We worked together twice a week for 6 weeks. They really didn't need a trainer to do it, and I really tried to talk them out of doing it by the book. However, they really wanted to try it. So we did.
Both of them have since returned to me as clients, and are now training MY way. The conclusions that they reached are that 1) some of the exercises in the book really don't work "super-slow". In particular, crunches and hyperextensions; 2) depending on your size, some of the machines specified in the book won't work for YOU. One of the women I trained is 5'1" and is just too tiny to use a standard bicep curl machine. It will not adjust for her. We had to switch to using a bar or cable curls. 3) Some of the exercises in the book are the least effective for training the muscles that are being targeted. 4) It is really boring and excruciatingly painful for the payoff.
Both women did end up stronger. Neither lost weight or inches, but they weren't dieting. Both agreed that a more traditional approach to weight training, combined with cardio and functional fitness exercises would have yielded more measurable results. Since they have done both, they are speaking from experience.
I read the book and tried most of it before I trained them. The author requests that you send him notes about how you did or any suggestions or changes you would make. I got the feeling that he really didn't try it out on very many people.
If it sounds too good to be true, it usually is.
Mel