4.25 stars feels right on this. First and foremost, I'm not a big fan of the romance Cress gets involved in. I won't go into detail, so as not to spoil it, but I think it's a bit too cliche and I'm not feeling it. The rest of the book was really amazing though. I didn't actually enjoy the previous book as much as I though, but I am digging how Cinder is handling everything and continually developing as a character.
I feel like this is setting us up to an epic conclusion, and I'm eager to see where we go from here.