Story: I think Nana's story is quite good. Story is for females, about females especially in t18-25 age. I don't think its a josei/shojo, its between the two kind.
Art: Madhouse Studious. Very good graphics as intended with Yazawa Ai's very interesting and outstanding style.
Sounds: An anime based on music, shows a challenge between two bands, ofc, its really good in music.
Character: The character's are really good, but I think its quite imposibble to be from a countygirl to a celebrity in only half or 1 year.
Enjoyment: I really enjoyed the story but, I'm male so only 9 point. Sorry.
Overall: Watch this anime if you want something but not fighting animes with 229ö1 episode.