Arco GMAT: Graduate Management Admission Test, with Computer-Adaptive Tests on Disk

The Software accompanying this book was the closest ( other than Poweprep from ETS ) that I got to the actual test, as far as the look and feel. Content-wise, it does have some tough math, but overall, it gave me consistent scores which matched almost exactly to my actual GMAT. Make sure to go through the book before you jump to the tests. Improved my score by at least 80-90. With this book , PowerPrep and some tester practice from Princeton Review, I jumped from an initial 570 to 660. Worth every penny.

ARCO's guide for taking the GMAT CAT is very thorough and well-written, although it lacks the humor and "chatty" attitude some other lines of study guides are well known for. My only true complaint about this book is that it does not offer any interpretation of the scores you achieve on the practice tests -- you know what you've missed and why, but you have no way of correlating your performance to true GMAT scores. Sort of a bummer...