Of the two fusions, which would you say is over all the stronger union of fighters?
By way of the metamoran fusion dance, Goku and Vegeta become Gogeta. By way of the potara earrings, Goku and Vegeta become Vegito.
Both are limited by time, Gogeta 30 minutes and Vegito 60 minutes.The potara fusion however, is also limited by energy consumption.