If Touko accepts Sayaka's confession I'm going to be totally mad. Yuu did everything she could to make Touko change and begin to love herself and realize that, no matter how much she tries, Touko will never be like her sister and that is a good thing, to be who you are with your qualities and defects , because no one is perfect, no matter how much you love someone, you can see that and Yuu knows it. Sayaka was well enough to let Touko be the copy of her sister, to maintain the status quo in this matter, and even what she said now, about being all right for Touko to be who she is and that she loves everything about her, she was good with the Touko copy of the sister. I want Sayaka to have a happy ending, because I like the character and I can relate to her, but in the question of who would be better to stay with Touko, the answer would be Yuu who sees that she is not perfect, but loves her and always goes being there, helping her to be someone better.