In the fall of 2003, I applied to 7 top PhD programs in my field (in the sciences), including the 5 best. Although I had graduated from the top Ivy League university, I had worked for 5 years and wasn't sure how I'd present myself to the graduate programs. I had reasonably good GRE scores, but all of my recommendations were from industry, so I needed to massage my personal statement to reflect strong industrial experience.
Using this book as a guide, I completed great personal statements. This book helped me through the writing and revising. In total, for the 7 programs, I had the following #s of versions of my PS: 13, 10, 14, 8, 6, 6, 7, in order by submission date. So, you should plan on being serious about writing your PS and revising it carefully! 64 revisions of my personal statement may seem like a lot of work, but why would I want to be lazy and take chances with the graduate applications?
I was accepted into my first choice program (I only had 1 rejection - from my second choice program), which is ranked #1 in the country. The chair of at least one department told me I was the best candidate, and many faculty remember reading my personal statement.
Am I really that great a candidate? Well, I was fortunate to have great work experience, but I also owe this book a lot of credit in helping me communicate some of the insights I gained during my years of working.
I strongly recommend this book. It's a bargain and its advice is invaluable. If you're going to spend the time and money to go to grad school, why not submit the best application you can?
As for specific comments on the book: I think one thing many may overlook is the fact the book covers a lot beyond just essays. It addresses issues like communications with the faculty and department before you apply, while the application is being reviewed, and discussions you should have with your recommendation writers. This book covers many, many useful topics outside of the essays, and was invaluable in my overall preparations. Regarding negative comments: I can't think of any. The book was extremely helpful for me and others, and I can't think of anything to change.
I also recommend "Getting What you Came For", which addresses a few things that you should consider while you're applying to grad schools, and a lot of things you need to think about when you're in grad school.
As further testament to the strength of this book, I've given 2 copies to friends, and they've since gotten into the best programs in the country in their fields. I have recommended the book to scores of others.
Good luck to you!