Books which I enjoyed so much I would keep and read again and again.
Books I may keep and read again, but which had a few flaws which prevent it from getting the top grade.
Books I still enjoyed reading but wouldn't necessarily ever read again. They may have been rather bland or other factors, such as weak plot or characterisation, bought the mark down.
Books where I only enjoyed bits of it or found it dull. It could have been an effort to keep reading.
Did not like the book and may have found it very difficult to finish reading.