(I got a copy through NetGalley, in exchange for an honest review.)
Between "it's OK" and "I liked it".
I liked the premise of a Renaissance-like world, the focus on a castle that was like a city of its own, and the inner House politics. There was much potential here for intrigue of that kind, and I would've liked to see more of it—but didn't, because Lucien, while being at the heart of it, was also more of an observer or a follower most of the time. Follower of other people's wishes, or of habit, or of the plot itself. I often felt that he was submitting to, and reacting to the action, rather than making actual decisions.
I also didn't know what to make of the Orfani in general. The novel was too ambiguous about them, as if unable to decide what to make of them as well. They were both privileged and rejected, considered as witchlings, but why exactly, since they didn't practice magic? It was a bit strange. Perhaps, if played a tad bit differently, it would have made more sense.
The characters didn't leave much of an impression. I may have liked them if I had gotten to know them more, see them act more often within the confines of the intrigue web spun in Demesne. Stephania, for instance, seemed like a cardboard feature (her mother was worse), but I could sense a drive underneath, and I would've appreciated seeing it for longer than I did. Giancarlo was really detestable, and Golia as well, yet they were too one-sided. As for Lucien, the protagonist, he had his likeable sides; however, he was often too self-centered, and I could never fully determine if he was really gifted or kind of an idiot; if he failed because othre people made him, or if he did because he would've failed anyway. I think I actually preferred Dino, who displayed more cunning (in a good way) and resources.
On the other hand, I quite liked the world itself, with its feeling of being completely isolated, and its origins that may be quite different from that of a traditional fantasy setting (if I read between the lines properly, that is). The secrets shrouding the King, and his pet project, were morbidly fascinating. I would definitely have wanted to know more about this world.