I'mma just backup Supes here. Keep in mind the Man of Steel has had decades of media dedicated to him, all of which contain various incarnations and feats.
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1. Most stories portray him as a mediocre fighter. He HAS trained with more skilled fighters of the DC universe, such as Wildcat, Batman, and Wonder Woman. Goku himself, especially in Z/GT doesn't exactly boast much technique, really just high stats. If anything, I think Goku's only slightly above superman as far as hand to hand combat goes.
2. Goku needs spaceships for interstellar travel, and at best, flies around planets around Supersonic-Hypersonic Ranges (It takes them time to get from one point on the planet to another, even with their superhuman flight speed). Instant Transmission doesn't count as natural speed, being a teleportation technique/spell/etc.
Superman is also within the Hypersonic or slightly higher ranges, mostly casually though. He is well capable of space travel, which means he's easily capable of flying at the speed of light, and possibly higher.
3. Strengthwise, Goku had done some stuff as a kid, and at best he can probably carry a hundred to a few hundred tons as an adult, but coupled with his own ability and ki usage, his striking power probably gives out more strength than his lifting ability. Most iterations of Superman are well beyond the hundred ranges and into the upper thousands as far as strength. In some stories, the man of steel HAS pushed entire planets.
4. Energywise, Superman does not waste much stamina with heat vision unless he's going all out with it, adding more concussive force to it rather than just heat alone to melt things. But that doesn't mean Goku isn't a more seasoned user of energy, having heavily relied on his ki for most of his battles in DBZ. Goku has the firepower to rain down some fury on Supes.
5. Durability? Well, both can deflect bullets. There's a start. But even then, Supes has flown through all kinds of things in space, like the corona of the sun at one point. That's essentially a hundred billion H-Bombs a second right in front of him. Goku himself can tank most anything under that of a planet buster.
6. As far as morals go, the two would still hold back a bit due to their respective personalities not wanting to hurt the other, even if the two went 'all-out.'