I, along with many others, was quite disappointed with the film. I have also read the book, which I thoroughly enjoyed and believe the movie did not do justice for.
My main issues were the lack of character development and random added plots.
Darby fell quite flat and didn't have the strength that we saw in the book. Jay's character development was ruined with the plot of her being mean. I liked how she was portrayed in the book and the movie ruined this.
The things that I did like was that they kept the setting pretty accurate.
Overall, if you have read the book, I would not recommend this as it's a butchering of the original plot and character development.
Once again, the movie adaptation will never live up to the book.