The author is well-regarded for his take on characters who already have in the zeitgeist a clear and defined personage, and also for his use of wordplay and voice. This book is no exception; when the narrative jumps from speaker to speaker, it does so in a way that does not leave the reader confused as each voice is so clear and so stark from one another. The characters presented are all clear and prominent and there's no confusion about who is doing what or where, which shouldn't be remarkable or distinctive but more and more is becoming so.
Mirror Mirror's entire arc is interesting, engaging, and as it builds on the framework of a familiar story, you find yourself looking for the edges of 'the next bit,' looking to see what elements from earlier play into the elements of future. This framework guides the reader and sets up expectations that can be subverted without being defied.
The weakest piece of the story to me was the conclusion; with the expectations I had, the subversion was not satisfying, nor to was the eventual fate of the villain. The trope page should indicate to any interested party that there are those who feel sympathy for the antagonists in this narrative; I find myself hard-pressed to do so. The emotional payoff I had been longing for in the whole book's life was cut short, meaning in three short pages, the book had ended and left me, leaving me without the payoff for which I had been hoping.
A less petty individual, or one with a pre-existing fascination with the Borgias, will likely enjoy this book more, and I did enjoy it plenty.