I know that each PR in Cal. is not individually owned. I'm not so sure how far Hyperlearning has spread, but it's a company that started in Southern California about 9 years (I think) ago by Steven A. Leduc (He's the one who wrote the physics section of the review). The Biology section was written by a lady named Judene Wright, who is by far one of the nation's leaders on MCAT knowledge. She's got her Masters in Physiology from UCLA, and can run circles around any Ph.D I know in terms of biology knowledge (I think she is currently teaching the Hyperlearning courses in at the Irvine, CA center.)
Anyway, to make a long story short, Hyperlearning was killing the competition in Southern Cal. and was bought out by Princeton Review for a very large sum of money. The only influence PR took out of the whole deal....their name on the corner of all materials that are maintained by Hyperlearning. You cannot go wrong with this company. So, if your local PR is a "Hyperlearning" center, I would say definately go with it over Kaplan. I know that so many people in my area chose Kaplan the FIRST time around, and switch to Hyperlearning the second...why are so many Kaplan people taking it twice? Because Kaplan does not produce the results that Hyperlearning does. Each individual class is taught by an instructor educated in that field (must have MS at least), as opposed to Kaplan who often has one person teaching all subjects. Also, there are no video tapes - everything is live instruction and tutoring. You can take home all the exams and work with them, as opposed to Kaplan who makes you go to the "learning center" to work on laminated exams that must stay at the center. And the materials are far better and more realistic to the exam - in fact, they're harder than the actual exam so that when the "big day" comes it's a breeze.
If you don't have a Hyperlearning center, I'm not so sure as to the quality of non-Hyperlearning PR materials. Hope this helps, and take care.