When I lived in Columbus Ohio, I always just got the cheapest 87 from the sketchiest corner store in town, most often the M&S Pizza on Georgesville Rd because they were almost 20-30 cents cheaper than anywhere else. I also frequented Cleveland as I have a lot of family there, and basically everything up there IS a sketchy corner store.
Now living in Lewiston Idaho, almost all the gas stations here in town (76, Chevron, and Nom Nom) are owned by Coleman Oil so they all get the same stuff anyway. We also have a couple Sinclair stations, a Maverick, a Circle K, two Exxons and a Cenex, and I usually go to the Cenex because they're a few cents cheaper than the others. Cenex also just happens to be top tier gas.
However I have never had any issues as a result of running non top-tier gas.