I would think of how much added strain driving the blower makes on the motor, compressing air driven off the crankshaft takes HP and adds strain on every part of the motor, before making the final decesion. As far as turbos I've been told that( by racers who use them) they do add additional concerns off the back side of the motor so I guess there are no free lunches. Adding boost into a motor definetily makes more power easier per C.I. than N/A motor do.
It can take 100+ extra horsepower to drive a supercharger even on a mild 600-700hp street engine, so the entire rotating assembly is going to see additional stress from the cylinder pressures over an n/a motor. However, for the same displacement the n/a motor would have to spin at higher rpm, which requires more expensive valvetrain components.
Both are cool. I like torque so I prefer big blocks, or supercharged/turbocharged smaller displacement engines.
