Gogeta Is The Strongest Super Saiyan Fusion, Not Vegito - Here's Why
The Buu Saga in "Dragon Ball Z" introduces the concept of fusion, which is possible either with the help of a pair of earrings called the Potara or synchronized choreography known as the Fusion Dance. Goku and Vegeta — the two strongest heroes in "Dragon Ball" canon, of course — fuse utilizing both of these methods at various points in the franchise, becoming Vegito through the Potara and Gogeta when the Fusion Dance goes according to plan.
Naturally, the simultaneous existence of these two similar but distinct characters has inspired plenty of "Dragon Ball" fans to argue passionately about which fused version of Goku and Vegeta is stronger. While compelling cases exist for either answer, Gogeta is the stronger character after taking into account one particular update to the series' canon in "Dragon Ball Super."
It's worth noting that a Q&A in a 2018 issue of "Weekly Shonen Jump," in which the "Dragon Ball" manga was originally published, described Gogeta and Vegito as evenly matched. Taking this into account, it can still be argued that Gogeta is a stronger fusion because Goku and Vegeta can sustain the transformation longer than they can remain Vegito. While Fusion Dance forms are limited to 30 minutes, Goku and Vegeta demonstrably cannot maintain their Vegito form for even that long during their fight with Zamasu in the "Dragon Ball Super" anime due to their overwhelming power splitting them apart. So, even if they're equally formidable in combat, they can remain Gogeta for longer, making the transformation superior.
Even arguments in favor of Vegito provide key evidence for a Gogeta victory
Discussions online dedicated to determining a winner between Gogeta and Vegito typically highlight the fact that the two characters are evenly matched rather than coming to any sort of strong conclusion, emphasizing their parity.
Perhaps the most thorough investigation into this matter is an entry in Rooster Teeth's "DEATH BATTLE!" series on YouTube. "DEATH BATTLE!" gives the slightest edge to Vegito based on two key factors: a technically longer time limit of one hour based on the Potara earring rules introduced in "Dragon Ball Super," and the fact that the Fusion Dance requires equal power levels. According to this latter point, Goku would likely have to lower his power level just slightly to match Vegeta's for the Fusion Dance, and that discrepancy would give Vegito a subtle but fundamental advantage.
However, the video also highlights a key difference between the "Dragon Ball Super" anime and manga that weakens the case for Vegito. During his fight against Zamasu in the manga, Vegito can sustain his Super Saiyan Blue form for about 40 minutes, whereas in the anime this time limit is far shorter. The anime version of Vegito, then, definitively loses any sort of time limit advantage. Vegito is further weakened by the fact that destroying the Potara earrings nullifies his fusion, which is very well something a fully powered Gogeta might accomplish, once again giving an edge to Gogeta in this match-up despite the video's conclusion.