The best book, in my opinion, will give you adequate depth so that you can understand the basic, underlying concept but not go into the low-yielding stuff. The low-yielding stuff is the highly specific details that really flesh out the basic concepts but are really unnecessary for the MCAT, as most MCAT questions will have you begin reasoning from fairly simple concepts. The new MCAT is all about applying basic concepts to complex situations and not how many esoteric facts you can remember from your biology textbook.
Finish content review as soon as you can and get started on practice passages and FLs. These are the true determinants of your score and after you take one, you can identify your areas of weakness and go back to review. If you need more depth in an area, you can always use Khan Academy videos - they are quite good (not to mention free!).