Depends entirely on your experience and level of knowledge. If your fairly new or uncertain about your skill level then by all means read the those big tomes of wisdom such as the Sybex guide you mentioned. Check out Eric Conrad's CISSP series as well as a good quiz book if you learn best by making mistakes or to get a feel for how fast you can solve questions. Just don't memorize your quizes. Do one and come back in a month for a better understanding.
Last I checked Amazon has a few hundred study materials as well.
It totally depends on your knowledge, experience, and level of expertise. If your fairly new or uncertain about your knowledge and skills level then you have to work hard and you have to use the all recommended learning resources to pass ISC2 CCSP Exam.
I recommend the JustCerts ISC2 CCSP Exam Questions that can help you to pass this challenging exam even in the first attempt.
However, for me, if I had a chance to take CCSP exam again, I will definitely read up and had a complete understanding of what is applicable LAW for EU, USA. For example, if a CSP is HQ in USA but has a data center in Singapore, which country laws will it need to comply?
Otherwise, CSSP practice/exam questions is not useful for me.
Instead of memorizing the answers, the correct way is to understand all the answers why is it right or why is it wrong. Then, apply them during the exam by eliminating the wrong answers.
With CISSP study materials still fresh in my mind, there are about 10 questions which I had no clue and another 10 questions 50-50.