if you're getting 34+ on average, give it a whirl; I used it and found it very helpful at honing my skills with trick questions and those that require test-taking skills to get out of. if you're in the 30 range, give it a try if you'd like, but there are other tings that will certainly help your score (and not hurt your pocketbook) more than this book.
that said, be careful- it is what it says it is. that is, if you invest the 25 bucks, get ready for a book of brutal questions that will make you question your intelligence. if you can keep that in mind, then go for it.