I haven't had much experience, but it seems like really classic good-looking guys are so full of themselves that they don't take the time to really make the girl feel special and to satisfy her needs, whereas an average looking guy will do that. That's been my experience at least.
haha well, i have had lots of experience, and what you said holds a lot of truth. sex isn't just about eye candy, even casual sex. i get orgasms from having my clit stimulated, not my eyes. and besides, arrogance is a huge turnoff.