I had both Kaplan and Columbia review materials. I am not familiar with EK. What's nice about Columbia review is that you don't have to buy all the subject books. You can purchase just physics if you want just physics. I hate promoting one company over the other b/c people always assume you work for the company. I don't, and I honestly thought CR was very beneficial, although all the companies are very good. Some of the practice problems on the physics practice exams were very similar to the actual questions asked on the MCAT. To state it bluntly out of all the materials I had (remember I did not have TPR or EK so I can't compare), the most useful for me were CR's physics and Orgo books, Kaplan's verbal video tape sessions (on the video tape of the verbal class the instructor spoke out loud what your brain should be processing silently while attacking each passage and showed how often one should pause to summarize--after several trials of trying to emulate the process I improved greatly...this worked best for me, but I don't doubt other people succeeded by different means), and AAMC's practice tests 4,5,6 (I had questions on the AAMC exams that showed up on my MCAT in slightly different form--the key is to go through all the solutions to the questions on the AAMC, even the ones you answered correctly. I hope this might help. Perhaps other people can write what they found beneficial about the other programs. If someone has a weakness in a particular subject then they can use these responses as a guide to choosing an appropriate program.