It's a fairytale, really. Which is a shame, because the concepts have so much potential.
Meyer understands that robots (or cyborgs, or androids) are only really interesting when they're there as a metaphor for oppressed and downtrodden humans. So she really builds the character of Cinder. You get inside her head, and yes, you can empathise with her. She's human, but enslaved, and we want to see her set free.
Beyond that, though, the other characters are fairytale characters, and I wish Meyer hadn't been so bound by the notion of a dystopian fairytale, because fairytale is mostly what we get and dystopia barely peeps through. Dystopia is peopled by complex characters, in a hundred shades of grey. Instead we get almost pure white or pure black. Kai, the handsome prince, a faintly troubled hero. The Lunar queen, whose name I can't actually recall, but made out of pure evil, and I almost hissed whenever she came on stage. Dr Erland has the role of the Fairy Godmother (with added Vulcan nerve-pinch skills) in case you weren't sure. Most of the characters were like that.
Except Peony. Peony should have been pure Ugly Sister, but she wasn't. Meyer wrote her as a morally weak person, vapid on the whole, but certainly not evil. I pitied her - I'm sure that was intentional - and I wanted a better outcome for her than Peony actually got.
Plot-wise, if you remember it's a fairytale, you won't get too many surprises. I'm sure the final reveal is meant to be obvious to the reader, for the hints are dropped very early and repeated, just in case you didn't spot them.
I won't pretend I saw all the plot twists - Meyer threw in some nice touches - but (like JKR with Harry Potter) Meyer also wrung maximum drama and suspense from having her protagonist not confide in the people who could have helped.
Just once, I really felt Cinder was in peril. It really should have been more, and the obstacles were too-quickly overcome - have you ever got in and out of a palace as easily as Cinder? And carrying weapons, too?
But I'm being unfair. This is a modern fairytale, and taken as such, it is spot-on. There are villains and heroes. There is comedy - poor Cinder - and tragedy - poor several people. There is peril, more often threatened than actual.
Taken as a fairytale, Cinder delivers what's promised, and on that level I don't feel shortchanged. It is entirely selfish of me to wish Meyer had maybe read Neuromancer just before starting this book.