I love Sarah Dessen and I've heard mixed reviews of this book. It wasn't her strongest, but I still enjoyed it. It was kind of funny how I could pick up on little things that have changed in her writing because of her life-changes... she recently had a baby and she had a character who was trying to have a baby and not successful. In one scene she's taking her temperature in the morning and Ruby assumes that she must be sick, but because things in MY life have changed as well, I instantly knew what she was doing (charting). I don't think that would have been in there 10 years ago.
There was definitely a message in this book, but I don't think it was as heavy-handed as I've read from other reviewers. Certainly not enough to detract from the overall quality. I'm a big Dessen fan though so maybe I'm biased.