I am in the industry of keeping gas stations up and running. From the registers / POS system in the store to the dispensers / tanks / turbines outside. We service all the major oil company corporate ran sites to small Mom and Pop ran single dispenser stations....
The question of " so where do you buy your gas from ? " is one I hear daily.
Based on the quality of upkeep on the equipment that stores and distributes their product is the main reason I make my choices. I avoid stations that allow any amount of water to be present / found at the bottom of their tanks. Many of these sites allow their tank levels to get very low before scheduling a delivery. Dropping fuel into a tank which is low and has water present allows that fuel to get agitated during the process. The whole time, customers are still fueling from those tanks. Sites that allow this also often take no precautions of having hydro-absorbing filters at the dispensers keeping water from getting by and into customers vehicles.
Sites can have issues with single hose / multiple grade dispensers not providing just the grade selected to be pumped into the customers vehicles. Some sites that run on a shoe string budget may wait months to pay to have this resolved. If the issue is in their favor 'You select 92 but but a lower grade is getting mixed in as well' many stations will keep that dispenser in service.
For me, I have minimal concern regarding the quality of fuel getting delivered to the gas station. It is what will happen to that fuel via the sites fueling equipment that causes me to fuel from one station vs another.
I buy my fuel from Corp owned Chevron stations and Costco but never from Arco stations. I avoid independent sites that look ran down. The overall conditions / upkeep of the building often reflects how they maintain their fueling equipment.
What stations to buy fuel from if paying via debit / credit card, especially if paying at the pump is a much more important concern to me by far