Hi, I just took the MCAT yesterday and saw this thread. I didn't do the Princeton Review course (took Kaplan online instead). I'd say neither strategy is totally perfect, but TPR's method sounds a LOT more sensible than Kaplan's. (Kaplan tells you to "pre-write" most of your essay on scratch paper, which would be a DISASTROUS strategy in terms of time.)
On the first full-length practice MCAT I took, I kind of froze during the writing samples and didn't finish either one. That was scary, so I realized I had to do something different. On the next 4 practice MCATs and the real test, I finished both essays with a minute or so to spare (which I used for editing). This is what worked for me:
1. SPEED IS CRUCIAL. IF YOU DON'T FINISH ALL 3 PARTS OF THE ESSAY, THE MOST YOU CAN SCORE IS A 3. This is why both Kaplan's and TPR's methods are a little dangerous, because if you waste too much time early on you won't complete all the tasks, even if you have the world's best vision for your essay. ONCE YOU SEE THE PROMPT, YOU HAVE ABOUT 30 SECONDS TO THINK AND THAT'S IT--START TYPING.
2. Don't put an example in task #1 (define the statement) unless a great one comes to mind immediately. (If it does, of course you should use it.) An example isn't required in the first task, but it IS in the second (counterexample), and if you don't have one there you'll lose points. So use most of your energy coming up with an example for #2.
3. Start each paragraph with a statement that seems a bit opinionated, then back it up in the rest of the paragraph. (Example: "The whole essence of capitalist society rests on the notion that competition benefits consumers ... .") Taking a definite stand on the prompt makes it a lot easier to think of things to say both for and against it, while being mealy-mouthed and vague will leave you grasping for things to say. Remember, you have to express an opinion, but it doesn't necessarily have to be YOUR opinion. In fact, if you express an opinion you don't necessarily agree with in paragraph 1, it will be easier for you to come up with a counterargument in paragraph 2 (the hardest of the three tasks).
4. Introducing your counterargument: Start with a phrase such as, "However, this is not always the case ... [referring to par. 1]," or "It is clear that there are exceptions to this rule ...," or "But we cannot be too categorical ..." and then go on to state the nature of your counterargument and the example that goes with it.
5. Conclusion: Start with a summing-up phrase such as, "As a general rule ...," "The general principle, then, is ...," or (if you're desperate), "In conclusion, ... ." Then briefly summarize the IDEA behind pars. 1 and 2, without giving any examples or details.
6. Tone: try to sound like a newspaper op-ed writer. Don't be afraid to find your inner BS artist!
7. Editing: only try this if you have at least 45 seconds left, otherwise you could end up in the middle of an incomplete sentence or phrase when time expires (could cost you points). First fix spelling mistakes, then style if you have time. If less than 30 sec. left, forget it.
Good luck everyone, and TYPE FAST.