I haven't heard of Clanaad yet. Nononono is about a ski jumping prodigy girl who just graduated in middle school and now pretends to be a boy, in order to fulfill her promise to her deceased family, which was to win a gold medal at the olympic games - as there is no ski jumping contest for women in it, and top teams/schools don't take women.
It's really tense in several ways... her personal life obviously is complicated, there is a lot of exciting ski jumping scenes/contests (I never had thought that such a thing would exist, a cool story about ski jumping) and huge ups and downs for her, somewhere between making friends, severe pressure in competition, maintaining her lie and so on.
On top of that, she is an extremely sympathetic character, it's very easy to like her and to emphasize with all of this.
I really recommend reading it, it's quite easy to get caught by the story within the first three chapters.
It's Seinen by demographic, but the story still is easy to follow and it rarely even touches the possibilities of graphic displays which seinen allows, obviously it doesn't need to as a story mainly about sports.