I think this is one of the best JLPT study guides out there as far as a quick-reference book. It covers over 100 grammar points using a clear and concise layout. There are sample sentences for each point and a mini quiz. Plus there are more comprehensive quizzes throughout the book as well as four quizzes at the end that cover all the grammar in the book.
I have only two complaints about the book. First of all, it's pretty dry. There are no story lines or consistent characters to follow as you go through the book. And second of all, there are no English translations of the sentences (there are of the grammar points). I was using this book with a native Japanese speaker, so that wasn't too much of a problem. And I do believe the updated version of the book has the English translations.
But with that said, I've found it invaluable as a reference tool when studying with other books or whenever I need to look up a grammar point quickly while writing Japanese. I definitely recommend it at the very least as a reference to have on hand for upper-beginner Japanese students. I think even lower-intermediate students would probably find it helpful as well.