Judging from their fighting styles, I say Kratos would win. A lot of his combos revolve around going around in circles. However, it also depends on how big of an arena they fight in. If its a closed up space i think kratos would massacre, though if it was a larger arena it would really be a great battle.
I can already see people using the "dante's enemies are harder so he has a harder time". That could be very true. However, keep in mind that it could also mean that kratos is so powerful he doesnt have a hard time.
This topic isnt about ryu, but what the hell. Again, comparing the in-game fighting styles it doesnt seem like ryu could beat kratos or dante. Not to mention the fact that he dies very easily (which makes him feel more human to me). But I dont know.