I liked this even better than the first volume, which I already loved. It's mostly slower paced, but it manages to be simultaneously E.M.Forster in space, chapter after chapter of excellent world building, and a wonderfully sharp critique of the modern world.

I do definitely recommend reading these in order. Direct references back to Ancillary Justice are explained enough that I don't think reader would be lost starting here, but I don't think I would have got anywhere near as into it without the setup of book 1.