TPR and Kaplan are equally good, if we go by results (e.g. improvements in ppl's test scores). The effectiveness of a test prep company depends on: (I) how well they teach exactly whats on the test and nothing more, (II) how well they teach effective time-management strategies, and (III) the extent to which they provide familiarity with the format of the actual test. EK does (III); Kaplan and PR do (I), (II), & (III). My judgements are based partly on the sheer volume of resources provided by each. Also, I don't see how two people (EK) can put together material that spans 2 yrs, especially if neither is competent in any of the fields from which the test material stems. As I implied earlier, most of the EK 1001 physics questions can be found in the standard physics textbook (I can give you an explicit reference here, if you're interested in doing the comparison for yourself). And some EK conceptual questions, such as "inertia is a measure of an objects resistance to..." are simply ridiculous. I cannot prove this, but I firmly believe Orsay and his brother spent a lot of time going through textbooks, and simplified the calculations for MCAT purposes, not to mention modify text for the purposes of creating conceptual questions.