Least to most favorite, for me it would be...
Makina > Michiru >Amane > Yumiko > Sachi
I LOVE Yumiko but Sachi's route is my favorite. The music, Yuuji in this arc, and the story just greatly satisfied me. Amane's was great but it was something that I don't think I'll be able to play again.
Although I rank the routes this way, I have to say that they are all good and came really close to each other.
Sachi's arc is really touching but Amane, Michiru, and Sachi are all really close to me. If i had to rank based on a 10 system it would go like this.
Playing this game will stay with me forever and i hope to one day find a gf who can appreciate its beauty. Now that i have finished the game, i can finally watch the show! I think i will post my thoughts here, considering this had become more of a Grisaia thread rather than a VN one