The JLA would probably win in a physical matchup, but the squadron supreme is a much better superhero team in terms of entertainment value. They are a flawed or what I would call more realistic version of the JLA in terms of character and powers. Hyperion has similar abilities as superman, but not to that level. He is an authoritarian, vengeful, a bit arrogant character who developed over time and improved. Superman is just perfect in any way and therefore boring. Hyperion revealed his secret identity to the Supreme World Lois Lane counterpart and broke up with her since physical love and having children between them would be impossible. Just think about it, if the fetus just has a tiny fraction of his strength, the mother would never survive the pregnancy, provided it would ever come to conception.