Nikki, Rachel and Roxy, top 3 easily. Only real Issue I have Is that I don't think going for a solo playthrough with Rachel or Nikki will allow MC to help Roxy, not a fan of having to leave her to deal with that shit unless on her route.
Rachel's route so far has been fun but expecting Prof Creepy Breeks to be an Issue at some point.
Roxy's route has been super wholesome and does make me feel guilt being on other routes at the same time, actually feel guilt with Rachel and Nikki too tbh.
Love Nikki, she may be slightly crazy with an addiction to casual ball fondling but I get the feeling her route could be as wholesome as Roxy's.