I wanted to like this more than I did in the end.  The world-building was excellent, I enjoyed the asides that explored the mythology.
I was a bit disappointed with the all-male cast, since the series is called The Queen's Thief. The plot twist at the end was too surprising,

especially since there's first person narration from the Thief's perspective. All thoughts about his true motivation being completely absent was very unrealistic to me.

As for the audiobook, I really disliked the narrator's choices. His Magus was very sneering, and after a while it really started grating on me, especially since he becomes a lot more sympathetic towards Gen as the story unfolds. His female voice was also very annoying, so I suppose the lack of female characters ended up being a blessing in disguise.
Finally, the main character kept whingeing and it annoyed me no end...