I'm going to start by saying I have watched the first 3 seasons of the show, so my review is going to inevitably compare the two. I only got through binge-watching half of the show, because I ended up getting bored with the storylines.
Overall, this was a good read. The writing is pretty simple. It feels like it is a lot slower than the show. I kind of blew through reading it, waiting for it to get suspenseful. But this first book pretty much just sets the scene for all of A's future antics.
Having watched the show first, the book was a little dull for me because I know a lot of what happens later in the series. From what I have read online, there are some differences between the two, but the first book is pretty much the same as the beginning of the show.
I do feel that many serious issues such as eating disorders and cutting are not presented responsibly in the book, which upset me. Bulimia is treated as a gross way to lose weight, rather than an actual mental illness. I think Shepard had an opportunity to discuss these issues, but just uses them as cheap plot points instead.
Also, the whole access to alcohol really confused me. I don't get how the drinking age works in the book's universe, because the high schoolers are often ordering alcohol in bars and restaurants.
Also along the age line, the weird older man dynamic was creepy and also inappropriately addressed. Again it felt like a way to intensify the plot, rather than actually addressing a serious issue.
So the book was pretty good. There were just a lot of things that unnerved me about it. I prefer high school stories that address serious issues adolescents face or offer an important perspective. This one is all show.