I have finally finished this book. I really love this book series; it is perfect for passing the official HSK exams. In addition, the vocabulary is exactly what is required for the HSK3 exam. The grammar is well explained with exercises in context.
However, the best part of all is the exercises. All of them are based on the structure of the official HSK3 exam. Therefore, when I finished this book, I took a mock exam and it was basically like doing another exercise from the book.
Previously, I did the same with the HSK2 book and passed the exam. Right after finishing that exam, I started HSK3, and three months later I took the exam. I spent 3 hours a day reviewing vocabulary, studying grammar, and doing the exercises from the book. Finally, I passed the official HSK3 exam.
This workbook provides everything you need to ace the test. I also like the exercises to distinguish lookalike Chinese characters. Strongly recommended!