I heard that the AAMC ones are not very indicative of the test, although I plan on taking them anyway. I've heard that these tests are harder than the real thing, but are pretty good at reasonably predicting your actual score. I want to take as many practice exams as possible (TPR+Kaplan+AAMC)...AAMC are available on the AAMC website, but do you have to sign up for the full class (TPR or Kaplan) to get all their practice MCATs? I'm hoping I could just buy them separately.