I also was surprised at the low ratings. While certainly not perfect, I liked it. I didn’t read the book, but watched it with someone who had (and who pushed me into watching it) and we both left it puzzled as to why it was so poorly reviewed. Maybe it’s a matter of expectations? Don’t go into it expecting a masterpiece (though you do get the impression everyone who worked on the film expected one) and I’m guessing you’ll have a better experience.