If you're questioning whether or not Sound Off is better than a knock-off, then you don't know Sound Off.
I started buying SOI because the variation in the shade of their blue was less than that of Whelen, and I've been buying SOI since because their products keep getting better and better.
Both the Predator I and Predator II lines are quality lights and always have been. I own or have owned Predator grille lights, a Predator dual dash light, a Predator quad light, Predator dual surface mount lights, and I'm now running two dual Predator II surface mount lights in my grille. I've never had a problem with any of them, and they've all been nice and bright. I got rid of my Talon and replaced it with the dual Predator dash light I liked it so much (don't get me wrong, I'm die-hard Whelen too).
If you want a cheap piece of crap, buy the knock off. You'll probably get about 10 minutes of use out of it. If you want a quality product that will last a long time, is bright as any other major brand, has some of the most bitchin' flash patterns on the market and I stand behind 100% (I'm a customer, not a dealer), then buy Sound Off.