As there are a lot of other reviews going over story and plotline I wont bother.
This is a solid book, a good piece of writing but - its nothing special. Compared to the author's first trilogy this book lacks a certain something or somethings - perhaps its the fact the lead character isn't particularly interesting, shes a pretty buttoned down, unemotional, non quirky kind of gal with a dose of steel a mile wide, or that all the characters are far less developed than any of those in the trilogy, or... well whatever it is, this book doesn't thrill like the First Law set.
Although this book is a standalone - it does help somewhat if you have read the trilogy first, some vague hand waving and nods towards the greater political sphere will fit with a much more satisfying depth if you actually understand some of the bit part players threats, fear and doubt. Without it, I should say that some scenes will come across as a bit light - Who, What, How now ?
In short, this is a fine book, but it doesn't emotionally engage like his other titles, its much more 2D, and reads like its going through the motions in places. Just... another... 1,000 words... and then I'm done with this chapter. Not that its ever boring. Its just not going to set your world alight.
I seem to recall the author fretting that this book wasn't as good as the First Law trilogy, and rationalising that not everything can be great, but maybe his mind was playing tricks on him and it would be great. I would say his first instinct was right in this case - good, but nowhere near best.