"The Broken Pieces" was a satisfying ending to a really enjoyable series; overall, I would rank it as the third best.
The two paladins, Jerico and Darius, again carry the story, and the conclusion of their character arcs were good. Valessa the shadow-whatever-she-is is interesting, and overall I thought her arc was fine, but it did seem like a repeat of Darius's in "Clash of Faiths". The main antagonists, Cyric, Luther, and Redclaw, were each solid. I did think that Arthur and Kaide, both "good" characters, had inconsistent "bad" moments, I think just for plot reasons which didn't quite work for their characters.
The plot moves well throughout, and the final big battle is really exciting. The very ending--as a non-spoiler I'll just say when really strange things happen--was still exciting, but I did think it was confusing. I was first attracted to "The Night of Wolves" because it was different from most fantasy books in that it wasn't about supergods battling for the fate of the world, and when the series ultimately does turn into this usual story it was handled well, but also I am just a hair disappointed.
Overall, "The Broken Pieces" is about a 3.4, so almost but not quite a 4, but well worth reading.