I am pretty sure, as the story goes, that the brothers who invented them, catered one to higher end city folk who think most chain food stores are beneath them, and one toward cost conscious people who live in the country but don't want to go to Walmart because they think that is beneath them.
I like Aldi for some types of shopping, and you get weird European brands there . . . and I like Fresh Market for produce and the unique things you can find. I like Food Lion, because they are throw back and close, and I like Costco because of the cost to what you get ratio.