I loved the world-building, the supporting characters, and the heroine, Mina. This would have been a four-star from me if the hero, Rhys, the titular Iron Duke, wasn't so unlikable in such a big, stalkery way. I hated him so much I wanted to reach into the book and punch him.
Seriously, though... later in the book it's implied that he apparently had been sold into sexual slavery as child, but knowing that... while I'm sure that messed up him and his views about sex, it does not excuse him for being, pardon my language, a rapey asshole to Mina previously. I feel like he should have been more aware of what he was doing to Mina because of his own experiences.
Anyway, I hear the other books in the series feature less jerks, so I will probably give the author another shot.