I must admit a soft spot for Sybex (and Ed Tittel) study guides, having used them extensively for Microsoft exams. This book follows in that tradition, providing a good balance between detailed explanation and comprehensive coverage of the exam topics.
The bundled CD is useful. I raced through the 250 flash cards in an hour, which is good for jogging the memory. The four bonus exams, of 75 questions each, are good, but are not as difficult as the real thing. These exams provide grades broken down by each CISSP exam domain, which is excellent for identifying topics for revision.
One book can not guarantee coverage of all CISSP exam topics, particularly given the long list of references on the CISSP suggested reading list. I also skimmed through a friend's copy of Shon Harris's "All-in-One" exam guide. I would still rate this book higher, but Harris's book covers some topics in more detail then the Sybex book. The "All-in-One" practice exams are more difficult, though some of the questions are not clearly worded.
The biggest disappoint I have with the exam preparation experience is with the CISSP's ten domains. The examination questions are based on 'good exam fodder' from topics in the ten domains. The topics lean towards an academic approach to security, rather then knowledge needed by a working security professional.
The other references I would strongly suggest to help to gain a security brain, as well as a high exam score include: Stephen Northcutt's 'Inside Network Perimeter Security', Ross Anderson's 'Security Engineering', and Syngress's 'Special Ops'. Maybe I should take one of the SANS security exams, which are much more practical in nature.
And best of luck with the exam!