Biggest debate in the history of mankind.
They both have the potential to make substantial power, but it all depends on how your motor is set up, how many lbs of boost you are running, and the actual setups you have.
Turbo's big downside is turbo-lag, but this can be tuned down considerably
And Super's have a big downside (I think it can't make the power a turbo can at WOT, but don't quote me)
So I would say pick one and just go with it. :shrug: