As sort of a public service announcement for both Tekken 6 and Soul Calibur: Broken Destiny on PSP, they are both at the pinnacle of late PSP development. If you take away the resolution differences between the PSP and the Vita (which is not that great of a factor with the Vita's great screen) then these games could easily pass for Vita games. They look and play great. If you've been hesitant to check these out because they're crusty old PSP games, give them another look.
The production values for both games are certainly impressive, but they are two of the worst installments in their respective series. There is no reason at all to play these if you have their console counterparts or earlier installments.