Just watched the promos and trailers of So-Ra-No-Wo-To. Many said that the character design is close to K-On!, but in my opinion it's closer to the character/facial design in Kannagi (- Crazy Shrine Maidens) whether it's the animation style/quality or small things like fingers, hair(style) etc. etc..
I think this anime series is very promising since it's directed by Mamoru Kanbe who has worked on several wellknown anime, e.g. Cardcaptor Sakura, Ichigo Mashimaro, Elfenlied, Baccano!, and the recent Denpa teki na Kanojo (OAV).
And the story sounds interesting: "The story of the anime is set in the future on a land that, after being devastated by long-lasting wars, has settled into quiet decline. Model and actress Juri Aikawa will play Kanata Kumika, a 15-year-old girl who fulfills her dream of enlisting in the army and joins a unit of five girls who protect a fortress. The girls also play music that reverberate across the skies over towns without people and seas without fish. " (source:
ANN)