The breaks between characters, or the breaks between chapters - this is difficult because there are chapters that go from present to the past. It really interrupts the story, and makes it difficult to read, or to stay interested in the characters. I especially disliked the ending, when it went from Eddie to Sarah.
I also have to say I didn't care how the story ended. It wasn't as if I didn't expect it, but there were things in the book that were misleading, and after the third or fourth time that it happened I realized I was getting bored and I didn't care anymore if Sarah and Eddie found each other or not. Or really what happened to Sarah in the end. After learning about the secret that tore them apart, I was even less interested, partly because it was obvious to me that it was a horrible accident and that some of it didn't seem at all believable. In reality, while this wasn't a bad book, it just wasn't a book for me, which is why I would give it three of five stars.
I also had an ARC, so I did notice there were a lot of grammatical errors which did annoy the English teacher in me. I hope that in the final draft these errors were corrected.