How much do they change in a new prep book edition?

Test Preparation AP Test Preparation
1

<p>Hey!</p>

<p>I have the 2009 PR AP Chem review book. I was wondering whether it was worth it to buy the 2011 PR AP Chem review book. Is it worth it? I am aiming for a "5." How much do they actually change besides the date from year to year? Also, is Princeton Review the best for AP Chem?</p>

<p>Thanks!</p>

2

<p>Uhh, the year, and the fact that there is no longer a quarter point penalty for wrong questions.</p>