AO will never escape comparison to the original season of Eureka 7. As I tried to stand it on its own and evaluate it, I really didn't get far, and I actually came away with a better opinion of the original (despite that show's propensity for dragging things out way longer than was enjoyable for me).
Overall, I thought that AO's "plot" was much less coherent and its characters less quirky and lovable, with the notable exception of the main character. A lot of my dislike of Eureka 7 stems from how downright obnoxious, whiny, angsty, and pathetic Renton was throughout most of the show. Ao was much less emo and annoying and I liked that he sprang into action instead of wallowing in negativity and self-doubt. However, the other characters were lackluster, *especially* the female characters.
I guess it was enjoyable enough, but ultimately it discards the heavy and thought-provoking themes of its predecessor for fanservicey character design and sparkly battles--and was it really necessary for adult-Renton's voice actor to be the same as Holland's? That really frosted my cupcakes.
That is all.