This is a recommendation - not a review.
The Rithmatist is a 'hard fantasy' for teens, and is absolutely excellent - fascinating, funny, exciting; with glimpsed depths of religious seriousness.
So far. It is the first of a planned trilogy, and of course final judgement will need to be suspended.
I read it once - on Kindle - then listened to the audiobook - and on second encounter I enjoyed the book even more, and found it even better structured than I recalled.
It will be difficult to maintain the standard of the first volume, but if Sanderson manages to do this; then the trilogy will surely become a classic.