Originally Posted by PratoN
I think everyone really should shop around, though. I've found a Thornton's station in Illinois nets me 38-39mpg per tank on 93 and then I fill up at the BP and my gas mileage instantly drops to 33mpg. It's happened more than once and I think it's more than just a coincidence / weather / driving style changes.
I have found Shell V-Power gives me better mpg's and performance, I could not tell much difference in other brands premium vs regular. This video is a couple of years old but it was a comparo between BP Ultimate and Shell Optimax/rebranded now V-Power and regular gas. Of course I am sure the fuel they were testing was not contaminated with ethanol.