The stuff with Harry & Margaret was great, as was Noah's early life in the wake of his father's death. I appreciated the attention to intergenerational trauma dynamics displayed throughout. However the conclusion felt... obvious? and the latter half of the book was a bit of a slog as a result, since it was leading to this overly-neat wrap-up. The monster stuff was also very underdeveloped in comparison to the family stuff. To be honest, as weird as the City was, I wish it had gotten a lot weirder. But the last chapter from Harry's POV made me cry so I've got to give credit for that. For the most part I'd consider this the horror equivalent of a beach read - fun, engrossing, and best if you don't think about it too hard. Which may be slightly disappointing if you were drawn in by promises of literary significance and an IWW alum author, but approaching it for what it really is, this book is pretty good.
I might come back to write out my thoughts, because I have too many right now (just after finishing) and I'm sure they'll keep coming. This book is a fucking tour de force.