I've read several reviews on this book that say it lacks the necessary depth; and I think they are a bit unfair. The objective of this book is simply to provide the least amount of information necessary to pass the exam. Conversely, many of the "larger" books contain information to teach the reader the subject, which may seem unnecessary to many who already know their subject matter. If you were to condense many of these books, you would end up with something resembling this one.
Many other books encourage the reader to memorize unnecessary information, such as vendor specific data, history or countless examples that aren't really relevant to the exam. In memorizing this unnecessary matter, it is possible to overlook more important items. Basically, more information is not necessarily better information. This is the objective of this book.
That being said, it would be extremely risky to rely solely on this book. This is because it contains the "least" information required, written some time ago, in an ever changing industry and exam.
I passed the exam recently using this book and the Official Guide. At first I started using the Shon Harris All-In-One, but found her very irritating and long-winded, so I dropped it (literally and physically). Interestingly she is the co-author for this book, and some would consider this a very condensed version of the All-In-One Book.
A lesser advantage of this book is that you can carry it and read it on trains, work etc. which I found very difficult to do with the bigger 1000 pager hardcover books.