The review formats vary depending on who writes them. At the very least, all reviews have a summary, the reviewer’s opinions/thoughts, and a official rating.
Book review ratings are based on a scale of 1-10
1-2: Horrible. I normally wouldn’t support burning books, but I think kindling would be the only solid use for this book.
3-4: Bad. The author needs to go back to the drawing board.
5-6: Meh. I didn’t loathe it, but it needs work.
7-8: Good. It made a decent impression.
9-10: Amazing. This book can do no wrong and I want to have its baby.
11: Super Amazing. This book is “slap you in the face good!”
12: Out of this world good. This book is a “forget your homework, don’t feed your kids, and quit your job one-sit read.” (Thanks to Jennifer L. Armentrout for the rating, via ONYX.)