This is why, imo, we should be careful comparing heroes from different comic universes. Not only is there the writer's intent for a particular story, but how the hero measures up in their respective universe. Superman is not just DC's flagship character, he is the icon of the whole superhero genre. He is supposed to always save the day. What other hero, eg, would warrant the "Thought Robot" treatment?
Surfer is not on this scale. First off, he is not even an A-list character in Marvel (let alone flagship), and stories about him rarely focus on his sheer brute power. Surfer is essentially a philosophical mouthpiece (why Stan Lee favors him), thus writers are not as *inspired* to take him to No-Other-Hero-Could-Do-This limits. I'm not even sure who Marvel's entry would be in this category. Sentry? WBH? But even then, these two don't have the inspirational aura Superman has. That would probably go to Captain America, and he, certainly, doesn't have that level of brute power.
This is why I go by averages + a gut-feeling when making such comparisons. Surfer and Superman can hurt each other.