But it's, gogetard. Vegetto said he was surprised he kicked Boo's ass so easily, he never thought he would be that strong.>inb4 he was wrong
Nah, Vegetto knows how strong Vegeta and Goku are and this last also had memories from the metamorean alien at the afterlife. He even knows how strong Goten, Trunks and their fusion is for a good and recent comparison. If [Goku+Vegeta] thinks his power isn't supposed to be that strong, then the fusion is way stronger than the one they would perform by the other method, so
[Goku + Vegeta + dance] < [Goku + Vegeta + potara]
so for short, potara > dance
Gogeta looks worse. Gogeta lasts less time. Gogeta requires of an awful dance Vegeta never learned and would never use. Gogeta is weaker. Goku and Vegeta metamor fusion would be objectively worse than the potara one in every sense.