Saiyans had tech also, and in a straight battle the saiyans would stomp because most of the kryptonians have almost no experience with that power, and the immunity thing was just for superman prime because he has a lot of invulnerability, regular supes krillin would beat because of; Solar Flare, Destructo Disc, Fighting speed and Fighting Technique, but that's only if supes doesn't run to the sun since Krillin can't breathe in space. Didn't Kryptonians mainly use Sunstone weapons to fight the wars? The saiyans would be fine against them.