As I read Fangirl, a book I heartily enjoyed, I found the Simon Snow fan fiction segments perfectly adequate for what they were (an obvious Harry Potter stand in) but not super interesting in their own right so I approached this book with a mix of curiosity and skepticism. My expectations were modest. In some ways this book exceeded my expectations, but it also had some of the flaws I anticipated. 
 What this book did better than I anticipated was make me care about many of the characters, even those who don't have large roles, and their relationships. I had a strong emotional connection to this cast. I felt like I had a good understanding of who these people were and why they behaved the way they did. I never wanted to stop spending time with them. 
 However, as much as I enjoyed reading this, elements of both the world building and the plot were pretty flimsy and generic at times, which I assume was inevitable given this universe's origins. Rowell takes an everything and the kitchen sink approach to fantasy tropes, tossing in a great variety of creatures and powers in an entertaining but also haphazard way. There's not a lot of originality here. What originality does exist comes more from the sheer volume of fantasy concepts that have been stuffed into this book rather than from a novel treatment of such genre staples as "the chosen one" or "internal strife amongst different magical castes." or "day to day life at magic school." So as strong as the character development is, and as enjoyable as the book is, it does feel derivative at times and elements of the world building feel rushed or muddled. 
 Even with these flaws, this is definitely a page turner, and you'll be glad you read it.