John Byrne gave us a very alien, sterile Krypton, with inhabitants that were implied to be hairless going by lack of eyelashes/brows, and the reaction of Supes' mom upon seeing an earthling. (please log in to view the image)
Did the Kents opening his matrix chamber somehow alter Superman's DNA? He obviously looked more human. Bulkier, with body/facial hair. (please log in to view the image)
Krypton's been revamped many times since then, but was that version of Supes mutated to a small degree?
“Individual science fiction stories may seem as trivial as ever to the blinder critics and philosophers of today, but the core of science fiction -- its essence -- has become crucial to our salvation, if we are to be saved at all.”
He's clearly much stronger then your average Kryptonian, looking at the New Krypton series. And DC policy has stated for years that Daxamite > Kryptonian. Superman being = to most Daxamites shows he's a particularly powerful example of his species.