A big shift from the previous book, with us learning a lot more about how The Superiority works. And some deepening mysteries, of course. Again, fast-paced, and kept me reading. I enjoyed MBot (and Doomslug, but that should go without saying). In true Brandersonian fashion, seeds planted in the first book (and which I totally called) pay off in the this one.
My big disappointment is how the exact set of tools Spensa needed to go on her mission dropped in her lap, essentially with a bow on. It felt quite heavy-handed, and I think spending a chapter or two spreading the arrival of the tools around would've improved the opening.