I recommend Cinder. 
 ***** 
 I do not read fairy tale spinoffs often. Beastly & A Kiss in Time by Alex Flinn were okay but it never sparked my interest to continue reading the same theme. Cinder changed that. The premise is unique and entertaining. Halfway through, I found myself falling for this book... but not quite at the end. I thought it was stretched long, or did the story started to drag on the 2nd half? Maybe. Still, Cinder is worth checking out. 
 Cinder was not a pushover, but... she does have a slight tendency to cower down (only a few times) because of guilt. Guilt over her sister's illness. Guilt over her being so different from everyone else. I loved it when she speaks up against her stepmom (such a bully). Cinder as a cyborg helped to take away the idea of "fairy tale Cinderella" per se. Cinder's sarcasm was also enjoyable. Prince Kai was in all ways charming. And befitting to be the Emperor of East Commonwealth. I thoroughly liked his scenes with Cinder. Electrifying and smile-inducing. =) 
 The concept of Lunars is the highlight for me. It was exciting to read about these moon people. I love the character of the Lunar queen - so dominant and badass! This sci-fi element was just right, along with the androids and cyborgs. Overall, the story was conceivable. It was a fun read! 
 Cinder is a good start for a series. The vulnerability brought about by the fairy tale retelling was balanced by the strength portrayed by cyborgs/Lunars. Could "happily ever after" happen to Cinder? I hope so. Let's see on the next installment, Scarlet. ;)