Acca,
I took TPR (actually, they call it "Hyperlearning" out in LA) in preparation for the April 99 MCAT. In my opinion the instructors were for the most part first rate, although the Verbal seminars could have been better organized and the OChem reviews were weak (and awfully rushed!). Regardless, after reading their entire review book and completing countless hours of practice exams I felt well prepared for the actual test. Honestly after completing the test I felt that I understood EVERYTHING so much better (I kinda wish I had taken the class BEFORE taking my undergrad classes).
Anyways, after all was said and done, I was pleased with my score, a 33R (12, 11, 10). From what I've heard from other friends who've taken Berkeley or Kaplan, the techniques utilized in most of the programs are quite similar. For what its worth, I think the key to succeeding with an MCAT prep course is to get down and dirty with the material--spend so much time with it that it comes out your pores. Truthfully I spent on average ~40 hrs per week studying or attending classes for the freakin test. It killed my social life for awhile, but if your gonna spend upwards of $1K on a prep course, do it right.
Best of Luck. Contact me if you have any questions.
Take Care!!