The concept, that's what made me read this book. I didn't know what to expect. 
 Overall, it is very light and easy to read. Even if the concept is thought provoking, I couldn't seem to feel connected to the characters and their constant indecisiveness. 
 After finishing the book, I confess I was curious to know more but not sure if curious enough to read the whole series. 
 Overall, pleasant read, very suitable for a young audience too.