Usually just the additives and marketing claims assuming the same octane.
In some cities the stations are all provided gasoline from the same refineries.
You definitely want to go to stations that sell a lot of gasoline so you are always getting fresh gas and it isn't being sucked from the bottom of the tank where sediment falls over time.
I buy most of my gasoline from Costco as they exceed all the additive requirements and pump so much gas every day it's always fresh, they also keep all their pumps in proper working order. The only time I ever bought bad gas was (twice) from small mom and pop type filling stations.