I have Swedish and KCs. I prefer my Swedish. They are calmer, larger, hardier in poor weather, lay larger eggs, lay consistently/daily through spring/summer. The KCs are skittish and their eggs aren't really any larger than my chicken eggs. The KCs are terrified by everything pretty much. I don't raise ducks for meat, but if that was a consideration I would choose Swedish over the KCs (the KCs are small, the size of a chicken). The Swedish girls lay just as many eggs as the KCs, so you can get meat without sacrificing egg production. The Swedish seem more willing/likely to go broody (not sure if that's important).