Superman has beaten both Thor and Hulk, he is clearly above.
Wonder Woman was shown as superior to Hercules and Wonder Man. Thor who has the same physical abilities as both (but is probably not as fast as Simon) has EP to allow him to compete.
The rest of the league has 2 herald level characters, 2 enhanced metas and the best street in comics.
Compare that to the Avengers, where a really powerful line up would be, say Thor, Iron Man and a herald level character like Sersi or Quasar.
The JLA vs Darkseid is a more competitive fight.
Yes, Superman has beaten Darkseid, but he's also shown consistency as beating down top end Marvel guys as well.
So do you accept that Venom is above Superman, Storm is above Wonder Woman, Wolverine is above Lobo, Thor is above Captain Marvel (Batson), Spider-Man is above Superboy, Silver Surfer is above Kyle, etc. etc.?
Superman and Thor fight as equals with Superman barely winning. Even Busiek confirmed this both in dialogue and in comments. Superman fought a rage handicapped Hulk. Hulk and Superman stalemate in Stern's book (isn't everything canon now in DC?).