I've always felt the main difference between the two was lag. With a turbo, you have to wait for it to spool up, but once it does, there is a shit load of power to be had. On a supercharger, however, the power is on demand, no waiting, but limited. Superchargers are also more reliable and from what I hear, boost your gas mileage by over 30%. Which never made sense to me.. if you're trying to make your car fast, who gives a damn about gas mileage.

Considering price and power, turbo is the only way to go in my opinion. H22As can even run on 6 or 7 PSI stock I believe. But in the end, the choice is yours... You better just make the right one!
Matt