I go more for Tsunderes myself.
Actually, it comes from the anime Mahou Shojou Madoka Magica. ...Well, that's one of the names for it. But onto the bit about Infinite Stratos, if that's the one that you were talking about, I'm a bit torn. The story is nothing special and neither are the characters. The most interesting thing about that anime would be the mechs and the setting. So it's worth checking out. I rather enjoyed it because I found characters that I really liked so I'm not sure about what your experiences would be like.