I finished it last night. Oof, that ending.
It definitely felt like the second half to TGO, so less of a standalone book than any of the others, which lets it down a bit. The second half was very well done though.
There were a lot of questions unanswered and some plot threads left hanging, which annoyed me. I was really annoyed at how one of the aspects of the book played out (not going to spoil it for anyone, though).
Overall though, I'll say it again: oof, that ending. There were a couple of things that I have questions on that I'll be posting soon!