There were a few things I didn't like. Was a little annoyed at the ending--I thought the two stories were going to come together somehow, and the mystery of the 80s kids would be solved. Also, Rob is an awful person and there were so many times I just wanted to punch him in the face.
But Rob was at least an interesting narrator. Even though I didn't like him, I was intrigued by his actions. Most importantly, I could not put the book down. I needed to know what happened next. The mystery was skillfully plotted, and the ending (of the Katy story at least) was satisfying.