Since a lot of the cultures of the spires are clearly coded to old time Europe, I wouldn't worry too much about where exactly the spires are located in the current US. Albion pretty clearly is victorian England, Aurora corresponds to conquistador Spain, the Pikers seem to be an analogue to the Caribbean pirates (I constantly had the main theme of Pirates of the Caribbean playing in my head whenever there were scenes with Ravenna). Not sure what exactly I'd attribute Atlantea (Atlantis?) and Olympia (Classic Greeks?) to, but the coding of the first three seemed pretty clear.
As for the story, it was very good. I was about to only say it was 85% as good as The Aeronauts Windlass, due to an important plot thread from the first book not manifesting itself, but then it did in the last quarter and that brought it up to being 95% as good as the first novel. I am very cross that Gwen didn't get her own viewpoint, though. She was the lead character in the first book until she got bonked on the head. Relegating her to a side character, so that a another character very much like her can take over her place in the narrative, didn't sit right with me. I hope (and think, given where she is at the end) that she'll be a main viewpoint character again in the third book.
As for the new viewpoint character, Abigail, I understand why she took over from Gwen, given that Gwen just isn't quite there yet in terms of position of power and proficiency, but due to Abigail having a pretty similar personality structure than her, just with more experience, it just felt to me that she was more of an interloper than a true protagonist. I appreciated the focus on Bayard, though, who is a badass. I also really liked Captain Ravenna (she must be the best Piker I've ever seen ^^) and I hope she stays around as a more prominent character. Bridget's side story felt a bit like filler, although it rounded out the worldbuilding. Really too bad that she couldn't interact more with the others, especially Folly, with whom she had made a good connection in the first book. The cats kinda felt unimportant and just there to give color commentary, which is a shame. Rowl had an important, active, role to play in book one and now he was reduced to trading barbs with a sassy kitten. I also had hoped to see Mirl again, but what can you do.
I do wonder what the population numbers of warriorborn are to normal humans. Given their physical superiority, they can't be very numerous, otherwise they'd have taken over power everywhere.
Also very interesting to see that at least one Archangel is still alive. Given Cavendish rant about what the real background of the world is, one wonders if they truly are as beneficient as portrayed here or rather more sinister. Of course her viewpoint is colored by being controlled by the Tyranima and being mad. And, damn, some chilling scenes with her, I gotta say. Especially where she giggled about eating people via the Mistmaw. I was honestly surprised at the effort to humanize her at the end of the novel. We'll have to see where that goes (my first impression is "redemption arc with self-sacrifice at the end to atone for the many monstrous things she's done").
We'll have to see what happens in book three, which already was said to take place on the surface a lot (small wonder with how things ended) by Jim in a recent Q&A. I hope it takes a lot less time to write than this one did, though.
