William,

None of us would be competent to evaluate the book. A person who would be is Christopher Check at Catholic Answers (catholic.com). But he is the president of the company and may be hard to reach.

Dear William,

I’m not sure if anyone responded to you at all, but here is my take.  

I haven't read this book, but in reading many of the reviews on it I would say it is worth a read. Keeping in mind that the crusades were highly influenced by a political context, one must not view them strictly in a religious sense.  

Since the author is Jewish one can say he is not trying to shill for the Catholic Church so at the very least his arguments will carry weight in a dialogue with non-Christians, more so than if the author was Catholic.

Peace,