The best feature of this book is that it makes you work on each new word. I agree with the authors on the fact that this is an effective approach. However, the words listed in this book are not quite the standard of GRE/GMAT. This book would be helpful to those who might be writing the SATs or are just beginning their GMAT/GRE preparation with a very limited vocabulary.
I don't regret buying this book at all, since it isn't very expensive and also i can use the "strategy" of this book with more complex words.