STP Oil filters are made by Champion Labs. From my observations (and pictures posted by others here) they are essentially identical to the SuperTech filters sold at WalMart. I'm not sure if the filter media is identical, but I doubt that it would be much different.
In general, I think that the SuperTech filter is a very good filter. Not the best, but IMO better than several on the market. The quality of construction is quite good. They don't have silicone anti-drainback valves, but most filters don't.
I believe that for the price, the STP filter isn't bad. You can buy better filters, but you pay much more for them and (depending how long you keep your car) may never see the difference.