I love Flavia and Basilio. They crack me up. I also really like Sully, Stahl, and Cherche.
Sumia might make me laugh ever time she does a faceplant, but aside from that I don't like her at all. I'm still working on my first playthrough with a male MU, but he's pretty bland so far. :\
I don't feel like I can give fair judgement on the kids since I haven't even utilized most of them (plan to with this play through.) I did like Noire the most and Gerome the least out of the ones I did use though.