My rating system is simple. I rate on a score of 1 to 5.
1: I hated the book and it was difficult or impossible to get through, glaring grammatical or contextual errors.
2: The book was all right. It was difficult to get through, but I still got through it. Some grammatical errors.
3: The book was of average quality, but not something that made me go wow. A very run-of-the-mill read.
4: I enjoyed this book, but it is not one that I would necessarily jump on the rooftops to promote.
5: I loved this book! I would recommend it to all my friends!