I use the Q-book to review a subject after I'm done studying it. (i.e. finished anatomy/histo/neuroscince/embryo so I did the 1st 2 tests in qbook to see if I got it) This way I don't "waste" Q-bank questions which I do randomly (w. all disciplines selcted) to simulate real test conditions. I've heard that q-book is generally a little harder than the real exam.