I didn't entirely read the book, but skipped a few chapters, because they were not relevant to my situation. The person that I knew with Borderline Personality Disorder is no longer in my life, although the consequences of their behaviour still are. I don't think they will ever get treatment or even be properly diagnosed for that matter, so a lot of the book was not relevant to my circumstance.
I cannot say how the book compares to other books on the same topic, but it was certainly an essential book for me. I had thought of my experience as unique and often felt like I was describing a space alien when I described this person. (Other people often act as if I have as well.) Just reading the book confirmed that the problem was Borderline Personality Disorder and that has been an essential piece of information for me. It helped me understand why the person with Borderline Personality Disorder had acted as they did, how it had affected me, what it was that even happened and that I was not alone. Most of all, it gave me some insight into their motivations for their actions and words that to me were inexplicable.
Because of that it will be a life changing book for me. It has answered questions that have plagued me for many years and I highly recommend that anyone who even suspects that they may be dealing with a loved one who has Borderline Personality Disorder read the book immediately. It may be that other books on the same topic are better, but I feel that a lot of things that had made no sense before, suddenly make sense now.
Update: It is now clear that this book contained exactly the information I needed to know and that it appears to be better than equivalent books. It has allowed me to coherently describe the behaviour of this person and to provide an explanation for it that makes complete sense. As a direct result, people now are capable of acting appropriately in response.