Powerdyne warranties the Ford Racing Superchargers (for two years like the ones they sell under their name). If you are looking for a street blower and don't plan on making alot of boost, then its not bad for the money. I'm very happy with mine. The install was easy and I haven't had any problems. People over at the Supercharger forum at the Corral seem to be more positive about them then here. I got mine brand new with a warranty for $2000 and I couldn't find a used vortech for a 94/95 for that amount (and I tried for 6 months - ebay, the corral, etc) and then you don't even know what your getting. If you plan on making more than 9 lbs of boost, then yes, I'd go for something else. If you overspin these blowers, you well break belts and possibly have bearing problems. At 9lbs or less they seem to hold up okay (they older ones got a legitimate bad rap) and if you do break a belt you can fix it yourself by getting the belts on ebay cheap. If you damage a mechanical blower, you won't be able to do that.
It all depends on your intended use and how much money you have. If money wasn't an object I probably would have gone for a Kenne Bell!