Let's break this down into the good and the bad.
The Good: Steve Stirling's world-building continues to be first rate, at a level very few writers can compete with. You can really feel immersed in the Changed world and see how the society and even landscape is changing over time. His craft in writing appears to have improved as well. He retains his cast of interesting and easily distinguishable characters.
The Bad: That said, this is a flawed book. It's primarily there to show the opening preparations and skirmishes for the upcoming war, with very little action occurring in the book itself. One of the primary plots takes place as a series of flashbacks scattered through the book - which means we know how it ends from the start. There are also a couple of occasions where important scenes happen "off camera" and we only see people talking about them afterwards. Steve Stirling also needs to rein in his love of describing food. People are eating in a lot of the scenes, and we know exactly what they're eating in each one. And while he introduces a significant number of side characters, primarily from the Protectorate, they tend to be rather generically honourable and capable. The Protectorate's darker aspects are mentioned in passing, but we don't see them.
That said, and I'm aware I spent more time describing the flaws than the virtues, this is a good book, but not Steve's best work. It's also not meant to be read on its own, but as part of the whole series and as background to the action occurring in the next book.
And the next book hasn't been finished yet.