Gigakigan vs Uta: who would win?

Gigakigan favored — Slight edge (~55%)

Gigakigan · One-Punch Man · Base

Tier
7-C
Attack Potency
Town Level
Speed
Unknown
Durability
Town Level

Uta · Tokyo Ghoul · Base

Tier
LOW 7-C
Attack Potency
Small Town Level
Speed
Sub-Relativistic
Durability
Small Town Level

A heuristic estimate from normalized VS Battles Wiki stats: tier, attack potency, speed and durability.