There are basically two types of superchargers--positive displacement and centrifugal.

A turbocharger is a centrifugal supercharger that's driven by a turbine that converts the heat from exhaust gasses to mechanical energy. Belt driven centrifugal superchargers get their energy from the motor's crankshaft. The centrifugal types need to spool up before they start making mad power. The advantage of the belt driven centrifugal supercharger is that it provides boost in a more linear way, so it's easier to tune and tends to not run out of boost at high RPMs. Of course there are exceptions to every rule.

The positive displacement supercharger is always crank driven. Early "Roots" style chargers had no provisions for intercooling, but many modern ones do. The positive displacement supercharger's advantage is that it literally forces a certain quantity of air into the engine. They're the most linear, and therefore the most consistent to tune and run. The downside is that they have the most parasitic power losses.

For street use, a positive displacement supercharger can really wake up a 4-banger. You'll find yourself downshiftin less, and you won't need to thrash the motor to get the car to move out. The powerband will be wider and less peaky. Centrifugal superchargers tend to be peaky, and can cause your motor to have a dual personality--sluggish at first, then all the sudden tons of go. That's fun for a while, but less practical for the street. If you're racing, that drawback might not be as much a problem as it is on the street.