I don't even know where to start with this book. Or this series. 

Things I liked: genuinely very interesting and engaging theological/philosophical reflections. Analogs to Greek mythology that were fun sometimes (and infuriating at other times...).

Things I did not like: 
Throughout the series, but especially apparent in this book because it had to wrap up the series, it seemed that Palmer's interest in characters and ideas and plotlines varied wildly, and so she picked up and dropped them more or less at random. Several plotlines introduced in the first book were resolved here after barely being engaged with for the middle two books, and the resolution... Fell flat, to say the least. There was at least one interesting philosophical debate introduced in the first book that was "resolved" in this book by a monologue by one character about how it is no longer a societal issue and an explanation by another character that it will be solved by the government doing research on the issue. 
Similarly, there was a real lack of consistency for several side characters, which had some degree of in-world explanation but really felt like Palmer had decided these characters were either more or less interesting than she had initially planned in the first book, and engaged with them much more or much less sympathetically for no apparent reason. 
A lack of plot consistency was justified by saying that the first book had been censored in-world, which was technically set up in the first book but was never engaged with in the second or third books and in this book felt like a justification to add or contradict things with no setup. 
Overall, this book felt inconsistent with any poorly connected to the previous books in the series, which is not what you want for the concluding installment of a tetralogy. Each book in the series has itself been fairly bizarre, all over the place, and incoherent, but this one was really above and beyond for that. Palmer is an ambitious writer, but does not seem to actually have the technical writing skill to pull off the project she has set up in these books.

And despite the fact that I have a long laundry list of things I disliked and that I think were poorly executed, and that I can't list many things that I actually did like about the books, I think I enjoyed them. Or, maybe "enjoy" is the wrong word; they were fascinating. Compelling, but not for the reasons I think they were meant to be. I would not reread them, I can't even genuinely recommend them to anyone else, but I'm glad I read them and I will be thinking about them for a long time.