After thinking long and hard about this, I'm gonna go with Kryptonian. Theoretically speaking, a Kryptonian can learn to do anything a Saiyan can do. Take Goku for example. Most of his abilities were learned from other races/beings. They are not inherent traits of Saiyans. If Superman were to train under the same masters that Goku had, then he would learn those same techniques too ON TOP of the abilities he already possesses as a Kryptonian exposed to yellow sunlight. Hell, Superman might even learn those techniques faster because of his super brain. But a Saiyan can't simply learn how to do whatever a Kryptonian can do. The things Superman do, any Kryptonian can do if exposed to a yellow sun. It's a matter of biology, not training. It's why Goku can't just learn to regenerate limbs like Piccolo can. Regeneration is natural to Namekians, not Saiyans.
So while a Kryptonian can do most things that a Saiyan can do, a Saiyan cannot do most things that a Kryptoinian can do.
Also, keep in mind that even if a Saiyan is really powerful like Goku or Vegeta, they can't keep it up for too long. They have a limited window for operating at full power. I know every fight takes like 20 episodes to complete but that's only a few minutes in real time. These guys start losing steam after that. I believe Superman can exert himself at full force for days at a time.