I thought the world was really interesting. I thought that the Prince's court with the Master of Assassins and all of priests was really neat, and though Khem was incredibly naive (and protagonists that miss the obvious usually annoy me) I still found myself rooting for him and enjoying his eventual success.
However, I thought the romance was barely fleshed out. I don't feel like I know Raine at all. There's just really not much character development in general (though the Master of Assassins was really cool and I'd loved to have learned more about him). And Khem's transition in thinking was pretty quick and not very believable.
Despite that, I enjoyed the world and the sense of humor a lot.