Didn't play through kouhai route and normal end and stuff. Here's my personal ranking on how much I've enjoyed each route.
Kazusa true end >>> Mari end > Setsuna end > Chiaki end > Kazusa normal end
Drkmerc's gonna hate me for placing Mari end over Setsuna end, but christmas cake route too cute. Setsuna end is overly idealistic and sugar coated in my opinion, which I feel does not quite match up well with the mood of the game. But Setsuna still a pretty good girl. Just that Kazusa is the best girl.
Aquaplus, do not disappoint me and give me Kazusa true end.
EDIT: Also, fk you Leaf for not having an Io end.