I'm a full-time test prep tutor, I've taken the Revised GRE, and I've written two preparation books for it (Barron's 6 GRE Practice Tests, and GRE Vocab Capacity). As such, I'm very familiar with the test (maybe a little too familiar).
This version of the ETS Official Guide to the Revised GRE is exactly the same as the old version except for a couple of important things:
1. There's a new paper practice test. This is great, since it brings the number of authentic GRE practice tests available to four.
2. Sample responses to the 2nd paper test's essays are included with grader commentary. This is useful since you can see what the real graders liked and what they didn't.
Things I like about this book:
1. The AWA (analytical writing assessment) chapter is well-written. Not only does it clearly explain how to score well, but it includes real sample essays (and there are more sample essays + commentary at the end of each paper test).
2. The book and CD have real GRE questions and tests (obviously). Using real questions is much more valuable that using those written by a third party because they are always more realistic and therefore are better preparation for the real GRE you're going to take. The computer tests are exactly like the real GRE I took.
3. The book covers all question types and math concepts.
Things I don't like:
1. The question explanations are often inaccessible to the average student, too technical/highfalutin, or too presumptive that the student understands certain concepts. I realize that the book can't explain everything, but more question explanations could be written in layman's terms. Similarly, the math review goes into too much detail about certain concepts and skimps on others.
2. The strategies in the book are not very insightful. Any good tutor or test-prep book can offer more helpful strategies than this book - but I guess we shouldn't expect ETS to give us the best tips on its own test - just like we shouldn't expect the IRS to tell us how to save the most money on our taxes.
3. The CD is only compatible with PCs, not Macs. I don't think any of my students use PCs anymore. (I live in San Diego, but I suspect most GRE test-takers, or a large percentage of them, only have Macs).
The practice tests on the CD are the same ones you can download from the GRE website for free (but they're still PC only).
Overall, this book is essential to prepare for the new GRE, and your time spent with it will pay off. Even if you think you're very good at math, verbal, and/or writing, mastering the GRE demands getting used to its format, quirks, and nuances. I strongly recommend that you supplement this book with another source of practice tests/technique and with an experienced GRE tutor. If you're interested in my help, either in-person or via Skype, lemme know.