3.5 is a rating that needs to exist.
As high young adult fantasy, this book does exactly what it promises to do. So much so that I found fault with its predictability. I was calling events between 50 and 250 pages before they happened--a problem for me both because of the book's length and because I do rather like being surprised in my novels.
I was pleased, at the beginning, because the author was fairly forthcoming about the world and characters in it, but that turned to frustration in the middle because I knew what was happened, knew what needed to happen and was unwilling to suspend my disbelief that the main character did not. To me, elements of the story read like the author was imposing a certain amount of willful ignorance on her heroine in order to up the stakes and create a larger catastrophe. Catastrophe is fine, but when it seems engineered, I get cranky.
The predictability of the storyline (obviously, all genres have their rules, but I shouldn't know everything that's coming) and the sense that the author wasn't allowing the character her own intelligence kept me from fully appreciating what was, otherwise, a really interesting book.

Also, I was deeply annoyed at the magical healing at the end of the book. Why must we take main characters with disabilities and heal them?