Well, if we are talking about the interactive sexual elements, then Daigneux wins, but story-wise I prefer Xao. She was a deadbeat on the verge of dismissal in our terms, but we as the playable went so hard in helping her and awarded with the much given 385 years of no invasion (I want to see Xao's response towards the aging playable character in the far future after the ending T_T). While Daigneux in a sense is also a failure, her kidnapping us the playable character via slave trader is something I find quite, not attractive. Although later we can shape Daigneux's feeling, well... Anyway Xao has anal scene even though it was just a CG event hahahaha.
While this may be seen as my stupidity and being noob, I find this game, Arrogant Kaiju Princess, harder than the previous entry