It's a good well written book, however it's not a very satisfying ending to the series. The series as a whole feels like more of a serial than a series, each with its own big bad to defeat rather than an overarching plot. 

The characters are interesting, however alot of the relationships seem a bit shallow and I wish they had been explored further.

There were some pacing issues in places it's very fast in others it drags a bit. 

The ending seemed quite rushed.

However despite my criticism, I did enjoy the book, and the series and I would recommend giving it a shot.