I'm in the same boat; been researching the two alternatives that I've found (besides Guillemot/Hercules), and I'm not impressed by what I've seen at their web sites. Anyone else tried one from Inno3D or Apollo?
If you want the original specs pyrok go with the Guillemot/Hercules as they were the first makers, but it you want to save a few bucks, go with the off brands. The thing I'm not certain about, it the overall quality of the product when going with the off brands.
ps.- if you do go with an off brand, keep me posted. thanks.