SST brake tech is from Wagner and sold exclusively under the Federal-Mogul line. Federal-Mogul owns Wagner and a bunch of other well known brands - like MOOG, Champion, ANCO, Fel-Pro, Ferodo, etc. Quite a few NAPA parts are actually rebadged Federal-Mogul parts. If they are make by Wagner - not sure. Could by a licensed tech sort of thing - Wagner provides the oversight and "recipe" for the friction material - then they make them at a Federal-Mogul factory. Not always a bad thing - sometime the quality can be improved by this method, ie. the factory is more modern, better QC. SST pads have a European ECE R90 certification, which is really tough - so they could be decent pads.
As for quality - again, don't know, never tried them. Not a whole lot of information out there outside of an on-TV plug twoguysgarage series. Cost wise, they are about the same as the Wagner's ThermoQuiet ceramic pads. Lots of people like them - but myself, never had much luck with them. They were quiet and had low dusting, but overall braking performance was mediocre. About the same as OEM. Couldn't get them to ever run right - eventually got them overheated and they quickly broke down afterwards.