Zero One easily: Now, I don't think Zero-One is the most amazing in comparison to Gaim, Build, and Geats, but Its still far better than Zi-O. I can sense more effort going into the story, and the characters to me have a lot more depth and personality to them. I can't call it overall good, especially considering what happened towards the end, but at least that had a reason why it turned out the way it did.

Zi-O was just painful from start to finish, no effort going into the story, the tribute episodes are insulting, and apart from White Woz, I don't like any of the characters, especially Sougo, who is a horrible main lead who never grows up.