Around here gas is gas. Shell, and Chevron, and Samco, and Texaco, etc from highest costing gas station to the lowest... all get gas from the same place. Top tier around here is bullcrap. I think it's bullcrap throughout the nation also. Even though I saw the information supracentral posted about top teir fuels... It's funny when you see a Chevron Samco, and other brands of fuel leaving from the same refinery, off the same lines filling up another gas station (Samco container filling up a CHevron station, then fill up a Samco mart, lol). Our "Exxon" right up the road just swapped the signs over to "MAPCO" and the same tankers are filling it up.
I use gas from a mom and pop, no ethanol gas place now. I just want to help out smaller businesses. One of those places you can imagine with two old fashioned analog pumps with just 87 and 93 available. Gas there is the same as "Chevron" or whatever.
Not sure about how other places do fuels, though. We have one local place where all the fuel is made and stored, and that's what everyone in this area uses from.