I'd say turbo, regardless, hands down.
There's much more potential, you make much more power, and it doesn't rob the power to make power.
Plus it's more tuneable.
Note that the fastest cars out there are turbocharged, not supercharged...with the exception of all out funny cars.
They actually don't allow turbos in that class, because they'd make too much power (based on what i read in a mag).