Vortech setups are much different than a standard Eaton-type (like a Jackson Racing) superchanger. The Vortech setup is a centrifugal supercharger, which is basically a belt driven turbo. The same high end power with not as much lower end grunt characteristics, same as a turbo, but it's a fixed drive, not dependant on load like a turbo. The Vortech systems are nice, but there is a limit to the flexibility as far as power, etc. goes. If you're looking for ultimate power and system flexibility, you might want to lean toward a turbo. I like the Vortech setups a lot, they're easy, reliable, and make excellent power for a street car. Get the aftercooled kit though, and the higher RPM drive pulley.

They're really both highish end power systems though. I would personally go for the turbo setup, because you have a lot of flexibility in turbo choice, intercooler choice, etc. that you don't have with the Vortech kit, unless you buy just the supercharger and want to peice together your own kit. I like to have lots of choices, so turbo setups are my preference, but Vortech kits definately have their place on street and track cars too.
Tough choice.

One last thing.. The aftercooled Vortech kits are over $4k I think, which can give you a lot of bang for your buck with a turbo setup.