Vegetto is a very powerful fighter. The downfalls are the need to enter hyper mode, making the fusion impractical against anyone who isn't retarded, and the fact that he is a potara fusion, meaning that if you fail the initial attempt, you are left with a watered down Goku/Vegeta for the rest of the fight.
Goku(Pre-fusion)
Vegeta(Pre-fusion)
Vegetto
Forms
Base--130% attack--6 ki baseline
Super Vegetto--145% attack--MAX ki baseline(7 ki bars required)