I kind of liked this book but didn't love it? I liked the memorable female characters, (Nina and Inej) and the story has an unusual texture that reminds me a lot of "The Lies of Locke Lamora". But it always felt as if I was kept at a bit at a distance.
This might be because the characters were all just a touch too cool to be true, too elegant, too much like stylised photoshop-artworks complete with outer-glow, than real flesh-and-blood people I could care about. They speak the language of "witty banter" rather than anything a real person would say, which made it hard for me to take them seriously. That's why I find it hard to achieve the suspension of disbelief the story asks. This is often the case - if a book has sold me on the emotional angle and I care about the characters I can forgive any number of "Would They Really Do That" or "Could It Possibly Work Like That" moments.
For example, why are the characters are supposed to be in their teens? They don't act or sound like teenagers at all, even toughened teens who were forced to grow up quickly. They actually sound more like soft-living, modern, American twenty or thirty somethings, in the way they speak and behave.
The more I think about it, the more the plot begins to unravel. You're told things about characters rather than being shown them, and that makes it hard to believe their motivations. But I did read it all the way to the end. The story has a sense of humour that I enjoyed, and a certain style, even if that style also meant that I found it emotionally a bit chilly and hard to relate to.