Best Fuel System Cleaner?

Ok, i was at Wal-Mart today and i realized that everytime i go to the auto section to get a fuel system cleaner(gas additive), i am unable to make a quick decision due to the different products. So there is stp, penzoil, mobile, prestone, etc…which one is the best fuel injector/carb cleaner for our car? I got the Stp injector/carb cleaner in the white bottle today for $1.64. Are these things worth it or are they just a waste of money?

i put gumout extra concentrated injector cleaner in everytime i do an oil change
i guess it helps