The best part about this book is that (if you're a Percy Jackson fan) you will recognize some of the characters and references -chapter 48-. This is awesome because some of us just aren't over Percy Jackson. Also this book is more grown up compared to some of Rick Riordan's other books.
The main thing I didn't like about the book was how confusing it was. Also it was fairly similar to The Lightning Thief but so much that it is a rip-off.
Btw, for anyone that read the book, Magnus would win the bet.