<p>I used the Princeton one- it had really good tips for the Science section. I live in the Northeast where no one talks about the ACT at all and I had no clue what to expect. I decided to take the test on a whim, so I skimmed this book the day before and I got a pretty decent score the first time out. I would definitely recommend the Princeton Review version.</p>
<p>McGraw Hill science seemed enormously easier than the actual science sections of recent ACT exams. Perhaps one of the others is better for that section?</p>