So far, I've managed to keep up to date with the reviews. (That is, up to date with writing the reviews after we watch the episodes, not keeping up with the new episodes as they appear.)
Nana Maru San Batsu: Shiki is a shy boy, a real bookworm. And because he didn't dare speak up, he even didn't get the class librarian position! But the Quiz Bowl Club president gave him a paper with 100 quiz questions, and he knew all the answers. And his classmate Mari, who he's interested in, is really into the demonstration that's given during club orientation. She convinces him that he should join, together with her.
So it's probably a sports anime, but since it's a non-traditional subject, it feels quite fresh. The designs aren't that detailed, and it'll probably not be as good as Chihayafuru, but it's worth giving it a chance.
Princess Principal: A gravity-nullifying mineral is found, and it's used in massive airships, giving the Kingdom of Albion a massive advantage. But then there's a revolution, and the empire splits into the Empire proper, and the Commonwealth. Five girls, one of who is the princess of the Empire, attend a prestiguous boarding school for girls in the Empire -- and they are all spies for the Commonwealth. Using their abilities and their covers as schoolgirls, they conduct sensitive missions.
Pure steampunk with lots of political intrigue and (at least for the first episode) a really clever plot. It looks gorgeous too. One to watch.