Princeton and Kaplan I know have the same policies on their guarantee. If you score less on the real test than the diagnostic, you get all your money back or if you are unsatisfied with your score, you can retake the class for free. I know that for Kaplan, in order to retake the class for free, the only requirement is that you attended all the classes, made up missed classes, did all the written homework and did all the online homework. I’m not sure if Princeton has anything like that. I don’t know much about TestTakers but I heard its the best of the 3. It costs about $700 more as well. What resources do each of these classes give you? Which is the best in order to gain the highest possible score that you can on the SAT and why?