This is actually Yukari Takeba from Persona 3. In the game, when you max her social link, you get the power to create the Persona Cybele, whom we see her dressed as right here.

it kind of matches with the pic for Fuuka where she wears the same outfit as her maxed social link Persona.

Cybele is the "best" persona of the game XD

that's sort of debatable, it really depends on which one you appreciate more i think. or various other reasons to decide on such a thing.