I didn't use this site but they appear to be the same (almost exactly) as other sites that sell you a pdf of a bunch of questions. 

if you really want to guage your preparedness for the CISSP hit the practice tests on www.cccure.org.  There is NO better site for preparing for the CISSP IMHO.  I used the site extensively while preparing and feel it was what prepared me the most (besides experience) for the exam.

Also instead of buying that pdf of questions pickup Shon Harris's All in One Guide to the CISSP.  It is well worth the money.

d1spat3r