what it all really boils down to, TPR, kaplan, is this:
in either case, you're gonna pay 1300 bucks. You'll be taught by students who couls be younger than you, and you're effectively just rehashing material you probably should know from your intro classes. They'll both give you plenty of HW and ample practice tests. But, the most important thing that is going to determing how well you do on the test is YOU, how well YOU remember and apply your science know-how, how much practice and effort YOU put into it. So, outside of the structure of their review materials, there isn't really a huge difference.
Regardless of which or any course you take, lots of intelligence, elbow grease, and a shred of good fortune, are what lead to success on the MCAT