Well, here's the thing. I think people who subscribe to the movie version of events like her more, because in the movie it was her given Veritaserum and she told Umbridge about the DA.
BUT in the book, it was her friend who reported the DA, and not because she was given truth potion. In fact, Dumbledore remarks to Harry that Severus Snape never gave Umbridge real versitaserum! Cho Chang stands up for her b***h friend. Okay. Sure. I get it. You stand up for the people that mean a lot to you.
BUT this was a question of morality as well. The ministry was out of control, using discussing tactics on children and justifying it by saying A. Dumbledore was starting an army. I can't image they really believed that, because in reality it is SILLY. Her reporting to the ministry, especially when there were other people in the DA who's parents worked for the ministry and didn't report it, was immoral from my standpoint. Cho stood up for someone who committed an immoral act. So I don't like her.
But she did, yes, at least, have chemistry with Harry. Ginny didn't.