This book is a prequel to the movie, The Descendants.
Basically I think the only real draw back of this book was that the scope was insanely large. This book tells the tale of the children of fairy tale heroes and villains. In doing so, it tries to rope in decades of characters from Disney movies. Because of this, sometimes the writing, especially the dialogue, doesn't always ring true to the original characters. There were times when I couldn't imagine Genie saying that or Flounder acting that way. It felt like really loose fan fiction with the original Disney characters. De la Cruz had some big shoes to fill with those characters, so we can't really fault her for not getting them just right.
However, I thought the new characters were pretty well done. I saw the movie first and felt like the book set them up decently. They aren't particularly deep characters, but they face issues that young readers may relate to (parental expectations). On the whole, this book is good for young readers. The text is simple, yet descriptive and pretty well-paced. The shift in focus for the narration also made things more interesting as the narrator followed each main character alternatively (Mal, Evie, Carlos, Jay, Ben)
It did bug me that there were multiple grammatical error in the text, but there were relatively few so it didn't take away from the book very much.
Overall, a good story, especially as a prequel. It sets up the movie nicely and adds a new twist to fairy tale retellings.