The whole book is just about the characters figuring out that Cinder is in fact princess Selene. 'The plot twist' the reader could guess in the first half of Cinder. Still the plot and characters are simplified to such an extent that for characters as Thorne or Kai and even Scarlet, Cinder Linh remains a huge unsolvable mystery.
It bordered on the ridiculous, so much I laughed out loud when Cinder revealed her true identity to Thorne and Iko around page 400. I'm seriously questioning Thorne's (actually every character's) intelligence in this series. Cinder practically told Thorne she was the princess and he's still completely mystified.
And I finally found out why: there are huge communication problems in this series. Sometimes on purpose. Characters would ignore each other, not listening what the other has to say (Cinder & Scarlet). Or they would just tell the other to shut up about it because what said person is about to say is not deemed important (Scarlet & her grandmother). Also Scarlet's mind is constantly clouded when she has to remember something crucial as associating Cinder with the cyborg girl mentioned in the news headlines or with princess Selene.
Cinder as being Lunar/cyborg/princess is the central character of the series and (with)holds all the essential information. Information that could further the plot if she would share it with her entourage
I had the same issue with Cinder but in Scarlet it takes epic proportions.
At first it was interesting to follow Scarlet's relationship with Wolf until it took a strange turn at the end of the book and they proclaim each other's soul mates after knowing each other for two days. I liked the fact that Scarlet kept her distance when Wolf first showed up. She didn't trust him right away and kept being distrustful towards Wolf for half of the book. Then Wolf betrayed/lied/tried to kill her and although we learn that he was being controlled, Scarlet goes from despising him for what he did to declaring her eternal love.
About Kai: I don't know what he's doing. He is telling himself multiple times that he's an idiot but he never does something to prove he isn't. Actually his decision at the end of the book confirms he is indeed an idiot. I can't understand his logic.
Let's say that the romance and the love interests in this series are not the reasons why I come back for more. I think it more interesting to see how M. Meyer handles the retelling of fairytales set in the futuristic world she created. I like the idea and want to see where she goes with it.
So nope, in my opinion, Scarlet isn't better than Cinder since the same issues come up again and new ones are adding. Also, the story picked up around page 270, nothing exciting happened until then and my mind wandered often.
I guess book three (Cress) will be about Kai figuring out that Cinder is princess Selene. And I'm sure he will be shocked when he does. The only way to find that out is for me to read the next book *sigh*.