The Magician King by Lev Grossman is exactly what I hoped it would be. This is a fast-paced magical adventure book with fully developed characters working together to solve a complex existential problem. This book has all the big magical battles which the first book did not. If you got into this series looking for full-apotheosis mode magical American teenager warriors, this book delivers.
You can get the audiobook for free here.
I give this book a 10/10. Truly an enjoyable read which I will come back to, again and again.