Hi score780,
I work for Veritas Prep, so obviously I'm biased about how good our books are, but I wanted to shed a little more light on the question of why you might buy our books after buying
Manhattan GMAT's books.
If you have the
Manhattan GMAT books and are still looking for additional resources, I can assure you that the Veritas Prep books will not be redundant with what you’ve already studied. In addition to presenting over 1,000 new practice problems, the books will provide you with a strategic framework for approaching each question type and concept area on the GMAT. With the insight that the GMAT is more a test of “how you think” than of “what you know" (GMAC itself emphasizes this constantly), the Veritas Prep books are designed to take the GMAT content covered in other lessons and build upon it, demonstrating proven strategies to deconstruct the way that questions are written and to play the logical mind game that the GMAT uses to create difficulty.
As an example, and noting that this thread has already mentioned Data Sufficiency, the Veritas Prep Data Sufficiency book has an entire “what if” section that takes existing questions and poses “what ifs” – what if the inequality sign in the question were flipped? What if the first statement said “non-negative” instead of “positive”? Those kinds of thought processes are critical to success on difficult questions -– if you can think of all of the possibilities in any given question, you can learn to anticipate the subtlety that the GMAT authors use to add difficulty. As the difference between sufficient (e.g. “always yes”) and insufficient (e.g. “usually yes, but there’s one exception") is often slight and may come down to that one number that you didn’t consider, learning to test the boundaries of Data Sufficiency statements is extremely important, and the Veritas Prep books are designed to show students the ways in which the authors test those boundaries, and to train you to think the same way.
Hope that helps!
Scott