Barron's study books... helpful or not?

<p>Hi, I'm planning to take SATII subject tests in a couple of months. From what I've read around the forum, Barron's study books tend to "overprepare" the studier. I was wondering, with enough time to work through them, does this overpreparation help you or was it just unnecessary extra stuff to memorize? I'm particularly interested in Barron's guides in regards to Chemistry, Math II, and World History.</p>

<p>Also, I've heard PR is good for Chem and Math II, while Kaplan is good for World History. Is this true?</p>

<p>Thanks for your help!</p>