There are people fairly deep into the 11s with the maggie. It seems like the guys getting down into the 10s are usually STS turbo'd.
I have always been a big fan of PD superchargers, but there is a point where you just can't really make any more power with them due to heat/detonation.
If you want something which is street-friendly, does great burnouts and has only mild upgrading routes, then the maggie is the way to go.
The STS is also street-friendly, it will provide a bit less low-end torque/hp, but you can pretty much always stuff more boost into the engine, or chang to a larger turbo for HUGE hp/tq. Obviously, there's a limit there too though...you just won't find it as quickly.
The procharger is somewhere in the middle.
It all comes down to what you want and how far you want to go with things.
Good Luck and please keep us posted on your decision.