As a teacher who assigned this book to my students, and used it extensively in class, I am appalled that so many people hated it. If it was a summer read, and was not utilized properly throughout the year, then that was the teacher's fault for not having the wherewithal to take something so carefully written and not using it to help his or her students analyze their literature extensively. My students used it with novels, movies, plays, short stories and even comics.
This is a companion book, meant to be used to help readers understand and analyze literary works so that they come away with a deeper appreciation of what was written. If it was just thrown at someone to read as an assignment, then an injustice was done to the reader and the author.