she has a lot of the annoying tropes going for her but somehow i find it endearing instead. in medaka kun mona was just straight up a bitch doing this is exact stuff in the beginning to that eunuch of an mc but here its fine
If I had to guess, I'd assume it's because of Saki's attitude vs Mona's.
It's been ages since I read Medaka, but the way I remember it, Mona couldn't stand the blow to her pride of Medaka not being interested in her, so her whole plan was to get him to fall in love with her and then dump him just to boost her own ego.
Saki, on the other hand,
also wants Ashiya to fall for her, because she's a succubus and is hardwired to want all male attention on her and revels in it, but she just wants him to be attracted to her, with no intentions of dumping him, so it comes across as more genuine than Mona.