I remember a story about M&S in the U.K. Up until a few years ago they only sold their own brand food, which had a higher price and a higher perceived quality to other supermarket brands.

The story goes that their biscuits are made in the same factory and cooked in the same batch as other brands, but M&S required that their biscuits be taken from the centre of the tray where they were cooked in the oven more evenly.

I swore off Nilla Wafers in favor of store brands in the 90's because Nabisco ruined them by trying to extend the shelf life with preservatives so much that they were never crispy out of a fresh box and had an awful taste. Years later I discovered they changed their ways with a foil lining instead of the preservative overload but I still won't buy them.