Rod, you asked so I will oblige.
As a 20-year personal trainer & director of some of the best in the business, I'll say this:
-Are the theories presented in the book supported by clinical trials (the gold standard in research)?
-Is the diet easy to follow?
-Does it fall into the 35% or more protein category?
Reading the posts above, It looks like just another book diet (think Atkins, Zone, Carb attics etc which have all peaked then gone away for a reason). I can see it's very hard to follow, and probably requires lots of protien.
While you will lose wieght on it, if you don't keep the weight off for at least a year, and I mean all of it, you're probably wasting your time.
Here's the bottom line: focusing on protein, fat, or carbohydrates serves only to distract you from dealing with the real causes of overweight—too many calories and too little activity. The fad-diet gurus know you don’t want to hear that, and are all too eager to sell you their latest book. Your body weight however is a simple calorie-equation, and there’s just no fooling it.
Dr. Dukan, who wrote the Dukan diet (another fad diet) did get something right when he said, "today we live in a land of plenty and our problem is not finding food, but refusing it." The paleo diet is keeping you from many foods, so you're losing weight (that was Atkins trick, too.) If you can live that way, go for it!
For most of us, if you want to lose weight, my best advise is to start where you are at, and look for "easy changes" to improve the quality of your diet. Cleaning the junk out of your cupboards and fridge is a great start! Forget "going-on-a-diet," instead approach it as a lifestyle change. Take it one day, and one meal, at a time.
Having said that, if you are the purist type, are single, and always eat alone, you will get results on the paleo diet as you won't have the obstacles to overcome us married-with-kids folk do. However, I challenge you to keep all the weight off at least a year before you determine if the diet was succesful for you.
Best of luck!