Chrisjen Avasarala has rapidly become one of my favourite characters in fiction, and I think this book probably deserves a 4/5 star minimum for her alone. If I had to make criticisms... the plot is possibly a bit less tight than the last book; the male characters continue to feel a bit two-dimensional; and I can't escape the nagging feeling that such excellent world-building and plotting is a little bit wasted on "space zombies". But that's definitely veering towards nit-picking. Page-turny, with really fun character work and consistently good writing. I will be buying the next one imminently.