Trella was an interesting, strong female character that I could relate to without having anything in common with her. I enjoyed watching how her character grew and learned throughout the story. Which was great! I loved Riley too! He was so funny and sweet, and the whole bit with Sheepy was so cute! Actually now that I think about it, all the characters were great and interesting. I especially liked Logan and Anne-Jade, they were awesome!
I loved the world that was created! I've been finding that more and more I enjoy the world that authors create nearly as much as the story and the characters. Reminiscent of Logan's Run and 1984 and other such futuristic worlds it still kept a unique feel.