Sarah Dessen is really good about writing about difficult family dynamics.
I really enjoyed reading this, I enjoyed Sydney. She was a very passive but looking at the family dynamics she was raised in her brothers shadow and said many times she felt invisible, so I think she was written very well even if I didn't always agree with what she decided to do. I Loved the Chathams, I wish we got a bit more with Mac because he was lovely. 
My biggest issue with this book is the scene changes, they felt abrupt. She would set up a scene give us a small bit of what was going on and then flash forward, skipping over the drama (or at the ending the resolution) to put us in a new scene then flash back to what just happened to finish off the details. It was very difficult trying to keep up with it.