Liked it but they left out a few things.
The book starts out with the author's childhood and his mixed breed dog named Shaun. The dog was well trained and disciplined; he was referred to as Saint Shaun. Including a few minutes of this would have contrasted nicely with the hell on wheels that Marley turned out to be.
Also in the book Marley stood guard over an assault victim until the police arrived; one of the truly good things Marley did in the book. Too bad it didn't make it to the movie script.
Ranb