As the Spanish person I am, I feel like I'm saying that the men are "penis"
Are men supposed to be considered pretty? Handsome is more like it...
i thought vakker also meant handsome.
Could be. A more used translation is vakker - beautiful and kjekk - handsome.
how would they be used opposed to pen/pene?
Pen/pene - pretty. Same differences as in English when it comes to meaning, I think. They are all obviously positive descriptions, it depends on what you want to convey.