Greg has it right. All appliances by a manufacturer are of the same quality, regardless of nameplate. They only differ in features, capacity, and styling. Some manufacturers will reserve certain features for certain nameplates, and some nameplates are reserved for cerain marketing channels and geographic regions.
However, there is one tiny exception, and that is when a one manufacture sells to another, with the latter's name on the product. Example: The front load GE washer at Home Depot is a Frigidaire product. So it would conform to Frigidaire's quality level, not GE's. Another way this could impact you is that parts for this product would have GE part numbers and GE prices, which tend to be higher.
There are a number of common products that are made by one manufacturer, and marketed by another. Examples would be the front load washer mentioned above, as well as certain laundry systems (dryer over washer that can't be detached). Some Asian refrigerator models appear under different nameplates. Finally, all private label appliances sold at certain retailers are manufactured by the big four US companies: Whirlpool, Frigidaire, GE, and Maytag, although some of these companies are into this marketing channel more than others.