Actually, it is all delivered by the same trucks, yes, but that doesn't mean its all the same gas. That's like saying all oil is the same cuz it all comes from underground. It's all about the detergents they add to that gas in their sumps.

I worked at a gas station for a long time and always wondered why my delivery sheets always said chevron..? Like, I said, you're right about them all coming from the same place but top tier stations take pride in their quality gas. Just as Pennzoil takes pride and measures in making an oil that's better than the stuff at the 99 cent store by adding detergents that they've spent a lot of money researching and developing. Is it gonna perform much different? No. But do you perform much different whether you eat a steak or a piece of chicken? No. It's just a little extra way to baby something you care about.

Btw, I have switched to strictly chevron since vons has offered their $.20/gal discount reward program cuz now chevron is cheaper with the rewards than the cheapest place w/out them, and I can tell you from someone who used to buy the cheapest to now buying chevron that I definitely get better gas mileage.