I've set up both for drag cars and I'll tell you this:
The turbo is A LOT easier to control at launch.
The Procharger creates boost instantly which (at least on the engines I have done) blows off the tires or causes wheelies you don't want to do. With a turbo you can launch easy, hook up, and then the boost comes in for the rest of the race. Can be the difference between life and the alternative.

On the street the Procharger is more fun for the same reasons...