I actually like Amily. At first, I wasn't too interested (I don't see Mouses as attractive creatures, aside of being cute), but she's well developed. Talking with her is key. And she is probably one of the most "normal" (psyche-speaking) characters, with totally believable reactions.
Marble I haven't tried yet. Milking fetish isn't really my thing, and there's something I don't like of her, I rather prefer Isabella (who I didn't really paid attention yet). And again, his reactions make total sense for the character.
And I see a lot of Tamani hate lol! Personally, I don't care about her. I didn't let her fuck my male char, so she's no threat.
I just realized there's a character I don't really like at all: Phylla. Bugs actually turn me down (that damn swamp with the friggin damned spiders being the most annoying characters in the game -for me at least), and the whole "colony collective mind" really bothers me. Phylla is a character that I don't have interest to develop with any of my heros (male, fem, or herm).