Princeton Review's SAT History and Math

<p>Hi, I registered SAT Biology, World History, and Math Level-I. For Biology E/M, I purchased Barron's. I decided to choose Barron's for each subject and either Kaplan's or Princeton Review's for back-up. I noticed that Princeton Review's History are compsoed of both US and World History; also the PR's MAth-I and II are conglomerated together. </p>

<p>In this case, does Kaplan's is better or still PR's in SAT World History and Math Level-I?
Also, does Kaplan's is better or PR's in SAT Biology E/M?</p>