Today's auto fuels are made to a federal spec. There is no difference among the brands except octane and age. Back in the day, some brands would actually blend them with additives, no longer. There is some adjustment for winter and summer at the refinery. Like the battery example, it is all the same now. Shop for fuel based on price and convenience. Like many consumer items they try to lock you in with rebates, points, rewards, advertising, and credit cards.