Inasmuch as she has the best overall aesthetic among the five; I can't shake off the feeling that she, out of all the characters, is the least best girl.
I really like how she was designed especially in the legend that binds and I also want to say that contrary to what Nino says, all in all I like how she dresses!
Having said that, it seems to me that aesthetically Itsuki is the one that is drawn with more care ...