~ Guess it just boils down to the individual and their respective playstyles.
A lot of us (can't speak for everyone) choose to play AVNs to live vicariously through the eyes of another MC just to experience a simulated taboo environment where one can live out their fantasies that extend beyond the mundanity of their IRL lives.
So, all that is to say is that it depends on your vantage point and what type of scenarios you want your MC to be exposed to.
If you're into a fat/loser/ugly bastard MC who ends up being the star of his show (Netori) style and steals all the hot women away from a secondary character (e.g., let's say the MC's bully who is tall/athletic/good-looking). AKA the undergo scenario.
Or, if you want to play the male equivalent of a Mary Sue type character, that uses his good looks and irresistable bad boy charm to fuck with all the women in his harem, that would be akin to that of a sexually indomitable scenario.
Ultimately, it depends on your play style preferences and how you want to envision yourself as you are playing through the eyes of the MC in-game.
Different strokes for different folks after all