It's been a long time since a book has kept me up because I want to read just a little bit more ... just a little further. 
 This is a thoroughly enjoyable read. I love the idea of different types of wishes, the world building is great (if a little uneven... more on that later), and Karou is a wonderful and engaging MC. 
 This is not really a spoiler, just not everyone wants to watch me be a pedantic twat ^_^ so I'm shoving it under a cut (view spoiler)[This book hit on a huge pet peeve of mine in fantasy: sterilizing an actual location or time period so that it loses all complexity and nuance for the sake of having pretty/glamorous scenery. Laini's Prague is a stale "gothic" tourist fantasy standing in place of an amazing real city (one that as a former resident I'm a little protective of for sure). Prague's magic comes from the clever way Czechs subvert and satirize the art and style of their unwanted rulers (be it Austrians, the Soviets or Western capitalism), a mix of high culture and dramatic low culture ... not pretty old buildings. 
 Laini's Prague never extends beyond the most obnoxious and horrific tourist traps (Cesky Krumlov *facepalm* GOOD GOD). Writing stories about residents of Prague hanging around Kampa and Old Town is like writing stories about New Yorkers doing nothing but going to Times Square and visiting the Statue of Liberty. It was silly and disappointing, something that a $5 travel guide or some lurking on expats.cz could have easily corrected. (hide spoiler)] 
 But that's not something I would hold against a book. Nah, this book lost a star from me for three reasons: 
 -The ever popular Instanta-Love trope >.< Doesn't hurt that basically every single character is supposed to be gorgeous in this book. Come on~ 
 -I wasn't overly fond of the characterization here. Sure Karou is great and at first I LOVED Zuzana ... but then she started to feel like nothing more than one of the cardboard "snarky bestfriend" characters that seem to roam YA Fantasy novels looking for MCs to set up for clever quips, and being the strawmen in normal world -vs- paranormal world dilemmas. I swear in the second half of the book she had absolutely no point. Akiva felt neutered to me and a lot of the characters from the first part of the book were quickly discarded in the second part of the book 
 -Which brings me to the third thing: the pacing was REALLY uneven in this book. I mean the first part is urban fantasy and the second part is high fantasy, and that in and of itself seems risky because not every reader likes both (disclosure: I detest high fantasy ^_^;;;). But in trying to keep the book's secrets hidden until the conclusion, all the world building for the climax was done all at once. The third and fourth parts of the book were basically the author vomiting up as much information as possible which was not really all that pleasant to read. It was also unnecessary, we know about the chimeras from the beginning, why couldn't the explanations about the various types and castes be explored gradually? 
 Overall, though, I would recommend this book: it was fun, it was creative and unique, and the ending.... oh God the ending was awesome :D