This was a really hard one to rate. It's hard to deal with a book in which pretty much every character is so unlikeable that you almost wish for a deus ex machina to get rid of all of them! I generally prefer to have at least one character in the book with whom I can identify to some extent.
On the other hand, the book is compellingly readable - as much as I kept saying how awful these people all were, I was completely sucked into the story, wanting to know how it was all going to end. The writing was good, and the very fact that I was able to work up SO much dislike for the characters is a strong indication of how well drawn they were.