for me, i found it more helpful to review more than to keep doing practice tests. once you understand the format of the test and the timing constraints, doing several more practice tests really has diminishing returns compared to spending more time memorizing the material. after my last proctored test, i had 6 days left until the real mcat, and i wanted to make the most of my time. even though i wasn't quite where i wanted to be in terms of practice test scores, i decided that if i memorized all the material, my score on the real thing would inevitably be higher than it was on the aamc tests. overall, doing most of the princeton review lessons + taking their 5 proctored tests brought my score up 9 pts from what it was on the first practice exam; memorizing all the princeton review stuff during the last wk brought my score up 5 pts on top of that.
another thing: don't overdo verbal. a lot of ppl i know ended up buying the examkrackers book on top of the tpr and/or kaplan books, doing all of the passages in each, and crapping out on the real exam. i found it better to just do verbal passages until i started getting a score i was fine with on the practice tests, and then i just chillaxed until the mcat. i think strategizing about it too much can really screw you up. and i agree w/ the above posters that princeton review's verbal strategy sucks. so does kaplan's. and examkracker's. i don't know anybody who has followed any of those and done well on the mcat. try out different things, combine a few helpful tips with what works for you, and come up with your own strategy.
back to the point of this thread: do princeton review. it has more class instruction, better review books, plenty of practice tests (if you want more, you should obtain additional aamc tests, not kaplan ones), and (this was really impt to me) its practice problems are in a book they give you. you don't have to have computer access whenever you want to do them.
anyway, i'm sure kaplan is cool in other ways. i chose to do princeton for the reasons i gave, but i'm not a kaplan hater.