Well. This was a little bit of terrific. And completely unexpected - I had absolutely no idea I'd enjoy this book so much since I am so skeptical about fairy tale retellings (a stance that I've had to reconsider since Once Upon a Time forced its way into my heart). 
 I was worried Cinder would piss me off too much, after all it is set many years into the future, Cinderella is actually a cyborg and so much shit happens that has absolutely nothing to do with the original fairy tale. When I started reading I didn't see it as a fairy tale retelling at all; I was convinced that none of the values or important plot points would be carried over and that, instead of a retelling, I was reading a bastardised version of a beloved fairy tale which was really only one step up from plagarism. 
 Don't worry, I was wrong. 
 [insert over-used "never have I been so wrong" Hobbit meme here] 
 Cinder is actually really well done. It really does have everything I want out of a book. The plot was excellent, fast-paced, spacey and compelling. The world building was interesting and detailed enough without overshadowing the plot. Little Miss MC, Cinder, was freaking awesome. She was strong and good-hearted and sarcastic as hell, but still has her flaws which truly make the character real. There was a good amount of focus on her condition as a cyborg too, something I was worried we wouldn't see enough of. Marissa Meyer took real care to weave all of the social and emotional connotations into the plot and it worked brilliantly. Best of all it was an easy-read, the kind of book you can finish in a day, but that isn't lacking in quality. It's the kind of book I'd recommend to fans of Sarah J. Maas as her 
 Throne of Glass 
 series has the same vibe. It's easy read intended younger audiences, but the author does such a good job with the characters, world building and plotting awesomeness that it can easily be enjoyed by readers of all ages. 
 In the end, I'm happy to call Cinder a fairy tale retelling. That's the whole point of fairy tales, is it not? Folklore told to children and adults alike to impart knowledge and life lessons. The setting can be continuously updated as long as the lesson remains. What does Cinderella teach us? That even a seemingly worthless servant can be important. That envy and wickedness will be punished, while optimism and perseverance in times of suffering are rewarded. And, on a side note, wouldn't we all just kill for an awesome fairy godmother? 
 Cinder updates the fairy tale for a YA target audience, creates a really interesting world and story that could stand on its own without being a retelling, but hey if Marissa Meyer wants to call it that then that's fine by me. I HEREBY DECLARE THAT IT FITS THE CRITERIA, and I know what I'm talking about when it comes to fairy tales. 
 I would have loved for Meyer to have updated the romance a little more, though. Cinderella and Prince Charming's love story has always struck me as ridonkulous (hello, insta-love), and in Cinder it really isn't much better. It bugged me that Meyer didn't seem to want to change that aspect of it, which is why I didn't give a full five-star rating. And while we're on the subject, what's up with the Lunars? Their existence is inexplicable, and I mean that literally seeing as Meyer just invented them, dropped them into the story and went "yeah, humans that evolved on the moon and have magical powers, they exist, what of it?" 
 When the book is overflowing with futuristic cyborg jargon that looked so technical and well-researched that I completely believed every word the author said, it baffles me that she didn't come up with some bullshit Lunar biology to explain their existence away. It didn't have to be a decent explanation (that's what the whole suspension of belief is for), but just bloody well come up with something Meyer, goddammit! 
 Sorry, but authors pulling shit like that really invokes my rage. 
 But other than those two teeny but also really fucking annoying flaws, I'd say you should definitely pick up this book if you haven't already, and also let me know what kind of bullshit explanation you would give for the existence of Lunars. NOTHING ABOUT THEM MAKES SENSE AND I CANNOT YET LET IT GO.