4.5 because of a couple of things I rolled my eyes at, but overall I really enjoyed it, more than the first one, and since that one was already a 4 for me, well...
The things I wasn't too convinced about: Devi's attitude regarding Rupert, a little too... forgiving, maybe? How she didn't realise sooner what the "trigger" to a certain other thing was, because it was pretty obvious. But I guess that considering the aforementioned trigger, it can be understandable (it's not so easy to be clear-minded in such cases). Also, one of her decisions when it was time to get some help; I would've expected her to turn to her friend back home, and... let's say I could sense that one twist coming.
On the other hand, I am so, so glad the romance part wasn't a strong focus in here. I still can't tell if Devi and Rupert will revert back to becoming an item of sorts, or if this will turn into something else. I hope that either the latter wins, or for some other development to strengthen the believability of a romantic relationship between those two. Anyway, there was a no-nonsense side to this subplot. Even though Devi could and probably should've been more ruthless, as said above.
The beginning/prologue: at first it chafed me, because it seemed to spring out of nowhere. However, it made sense later, and played well into the swirl of revelations and explanations. In general, those were handled well, allowing readers to understand more of what's going on behind the scenes, and to ponder about the decisions made. For instance, the sacrifice of a few people to save billions, or the use of biological (well, not exactly biological here... more like psychic?) warfare. "Handled well" is worth, too, for the bit about
from book one. That could have been lame, and could have led back to some cheesy moments... and it didn't.(show spoiler)
Rashid: I really liked this character, and the role he played.
Also confessing a personal liking for the Warhammer 40k aspect of the Paradoxian culture/army/way of thinking. I had had that feeling when reading the first book, before I saw the author herself acknowledged this influence at the end. It's a make-it-or-break-it aspect of the series, I suppose. It doesn't matter to me. Besides, armor porn for the win. There.