This is the first book that I used to study for the GMAT. While I found it to be a good introduction to the test, and the software to be easy to use, I found the test questions to be overly convoluted. The book tried too hard to create questions where you would miss a tiny subtlety and thus choose the wrong answer. I also found sample questions that were answered incorrectly.
I preferred the Princeton Review's Cracking the GMAT (for test taking tips) and the Official GMAT Review (for experience with real questions).

This book has good content. Covers the various sections in simple and crisp manner. The practice tests software is also very good. The only complaint I have with this book is the practice questions are too lengthy. It could cause you to panic that you may not be able to complete the test in time. It typically takes about 25 to 30 seconds to read 100 words. The average length of a question in the practice test is about 200 words. It means you take about 1 min to read the question itself, which means you will not be left with enough time to think, review specific parts of the question and arrive at your conclusion. This could lead you to believe you are too slow. Instead the length of the questions is not a true representation of the one you see in the exam.
Good luck!

For whatever reason, the study guides that Thomas Martinson creates - LSAT, GMAT, etc - are always user friendly, with understandable explanations and have been excellent tools in preparing me for these tests. The software is easy to use and realistic. The tips are helpful. Good luck.

I have used 6 different GMAT preparation guides in the past couple months, and have found many differences between them. ARCO's Master the GMAT has, by far, the best software. It is very user friendly, the questions are realistic, the explanations are easy to follow, the scoring guide offers exactly what information you want and none that you don't, and the interface looks a lot like that of the real exam. It far surpasses the software included with the Kaplan book, which I found to be second best, and is far and away better than any of the others (Princeton Review and Barron's are aweful). In addition, if you happen to have a hard time installing it on your computer (the software conflicted with another program on my computer), the support staff will get you up and running in under 5 minutes.
Unfortunately, I did not discover this book until the last week before my exam. Thus, I will not attempt to make generalizations about the text. If it is near as good as the software it is fantastic, and if not, the book is worth getting just for the practice exams.

Happy Studying!