FWIW, here's my mental definition of the 5 star levels when rating a book such as on Goodreads:

1 star = Bad. Didn't finish, or finished but really hated it.

2 stars = Not good. Maybe didn't finish. Had a lot of issues.

3 stars = Fine. May be entertaining but poorly written, or well written but didn't work for me. Had some issues.

4 stars = Good. I really liked it. Not perfect but strengths greatly outweighed the flaws.

5 stars = Excellent. I would read this again. This book has earned a place as a physical copy on my bookshelves. Few or no flaws.