Superman's superior power ceiling, versatile abilities, and greater feats give him a clear advantage over Omni-Man.
Both are immensely powerful flying bricks with similar power profiles. But Superman consistently demonstrates higher-tier feats. He has bench-pressed the weight of the Earth for five days straight, held black holes in his hands, and survived supernovae. Omni-Man's best feat is helping crack a planet with two other Viltrumites โ impressive, but Superman surpasses it individually.
Superman's heat vision, freeze breath, and super-breath give him versatility that Omni-Man lacks. Omni-Man is essentially a physical fighter โ fly fast, hit hard. Superman has that plus multiple ranged abilities and sensory powers that provide tactical advantages.
Omni-Man's advantages are his ruthlessness and willingness to kill. Superman holds back in virtually every fight. If Superman fights without restraint, the outcome is even more lopsided. Omni-Man's combat experience is also enormous, but Superman has fought threats at every level from street to cosmic.
Omni-Man's ruthlessness and willingness to kill immediately gives him an edge against Superman's tendency to hold back. His thousands of years of conquest experience exceeds Superman's, and his Viltrumite physiology is supremely efficient.
Superman has superior feats in every category โ strength, speed, and durability. His heat vision, freeze breath, and other abilities give him versatility Omni-Man lacks, and his power ceiling is demonstrably higher.
Superman wins through superior power and versatility. Omni-Man is a terrifying warrior, but Superman's feats consistently exceed his, and the Kryptonian's additional abilities make the gap even wider.
Omni-Man also fights
Superman also fights