I am once again shocked at the much darker tone The Circle Opens books have taken from the initial tetralogy, but it really works and I don't think it's too mature for children readers.  Briar continues to be my favourite of the four, and so far this is my favourite of the Circle Opens books, wherein Briar begins to realize some of the flaws of his upbringing while helping teach a new young magician, Evvy, who is an excellent addition to the cast and has a much stronger presence than the students of either Sandry or Daja.  

I also enjoyed Bruce Coville's narration in this one (more than I enjoy Tamora Pierce's narration in the other books.  She's an excellent author; she's not such a great narrator, I'm sorry to say).   

Sad Shatterglass doesn't have an audiobook and so therefore its going to take me a lot longer to get through it, but I'm hoping I"ll be able to find time throughout my semester to do so!