turbos generaly give more power, but at a compromise of stability. superchargers are more dependable, but tend to produce smaller amounts of power. it varies from car to car though, i think...
pretty much so ... the jist of it is
turbos = more power in the top end. turbos work off of exhaust pressure so you get a lag before it spools up. Can get more power than superchargers
superchargers = more torque and power in the bottom end. since superchargers work off of the pulley system you get all the benifits of the boost right away. more torque right off the line