I took it in January and got both the Barron's book and the Princeton Review book; both were pretty similar. The verbal section of standardized tests has never been my strong point, so I learned some pretty good tips on how to approach that section as well as the analytical writing section.
However, I must say that the quantitative (math) section of both books didn't really help me that much because as an engineering student, I've learned to use my math and problem solving skills to get the correct answer. On the other hand, the books seemed to assume that the reader only had the math skills of a ninth grader, so the method they try to teach you is kind of a trial and error, plug in all the answer choices type of approach, which I really didn't like since it can sometimes lead to an incorrect answer. So, I just skipped their strategies and worked the practice tests so I could familiarize myself with the type of math questions they ask.