Also here: https://www.amazon.com/gp/customer-reviews/R3B4AMYG58CT88/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=1119576067
Im a Harvard grad, 99% GMAT scorer and professional tutor/coach since 2002. I have taken the GMAT 5 times, with highs of 770 composite, 50/51 Quant, 48/51 Verbal (1 wrong), 8/8 IR (2 times) and 6.0 AWA (4 times), and I have scored in the 700s all 5 times I have taken the exam.
The GMAT Official Guide 2020 (currently $30) receives my strong recommendation because it provides a great source of over 1000 real GMAT practice questions at a decent price100 more questions than the previous edition, which had only 958. It also includes access to an online version of the questions in the book, as well as free access to the GMAT 2020 mobile app.
This newest edition of the GMAT Official Guide (OG) is still the gold standard for realistic GMAT practice. For optimal results, use it in combination with other learning and strategy guides. If you think that you need all 3 books at once, then go ahead and buy the OG bundle to save a few dollars on the individual books: However, keep in mind that many students buy the bundle and end up only having the time to use this book, which by itself has 1000 questions (the additional 58 Integrated Reasoning questions are accessible only through the companion website, accessible with a code, due to their multimedia nature).
You might also want to consider purchasing the 2019 edition instead. Everyone always wants the newest edition, but sometimes the price difference can be significant, and the questions on the GMAT havent changed at all since 2012, so older editions of the OG are still helpful (though the structure of the test has changed slightly).
I recommend the blind review method, where you buy two books: one for taking notes and one for keeping blank so you can re-try questions without bias.
Is this book enough for a full preparation? For most students, the answer is no: although the very best source of practice questions, the GMAT OG is lacking from a learning and strategy standpoint. In addition, the answer explanations in the book are often convoluted, overly simplistic and/or incomplete. Thus, it is a good idea to use online forums such as GMAT Club (which provide answer explanations to official questions, as well as question classifications and links to similar practice questions) and other GMAT strategy books such as Ace the GMAT: Master the GMAT in 40 Days by Brandon Royal to help you decode this complex standardized test. If you still need more help, then consider a class, an online learning program, and/or a private GMAT tutor.
For my full list of personal GMAT prep recommendations, google "GMAT Action Plan: How to Study and Prepare for the Graduate Management Admission Test."
Best of luck on your GMAT and beyond,
-Brian