I apologize in advance for any and all spoilers.
Going into this book having absolutely no expectations was kind of nice, because it meant I was pleasantly surprised. The writing style was done very well, and the story was definitely interesting and different from most other YA novels out there right now. Although some parts were pretty predictable (i.e. the Mirror Dragon is female), it was still written in such a way that you wanted to keep reading to find out more.
Also, I really liked that way that Goodman had Eon/Eona grow throughout the novel. It seemed like a sort of identity crisis at times, and other times it was more of a means of survival. Having Lady Dela there to help her through most of her issues without knowing it was also very nice. And as much as I kind of hate to say it, I'm kind of glad Heuris Brannon was murdered. I think he was holding Eona back, and that once he was gone she began to grow and mature exponentially.
My only real gripe about this book was that the chapters were so long. I prefer shorter chapters.
I really enjoyed the story, and I will most likely read Eona. Probably when it comes out in paperback and Paul buys it. I'd give this novel a 3/5.