I loved the Saizou/Charlotte support, it's one of my top supports in this game. Asama/Elfie is also in there and the Shinonome/Matoi one.
Surprising supports for me was Charlotte's, Joker's, and Flannel's. Although almost all of Flannel's support was him being cute.
As for disappointing supports, it's mainly with Zero. Everything is awkward with him.