Laura, Kemper is the same a Schrock, Diamond or Thomasville. They all come out of the same factory. Just a different label. Nothing special there. Medallion is a slight upgrade also available from some big box locations. Nothing special there either. Dura Supreme is generally available from dealers only. Some lumber yards carry it as well. They have many different options depending on the creative capabilities of your designer you might have some luck there. I assume you are referring to Decora cabinetry on the first one you mentioned. They are comparable to Medallion. It is an upgrade from Kemper. Also available in some Bog Box locations like HD. Try looking at Ultracraft, Fieldstone, Brookhaven or Vantage from Kraftmaid. In my opinion those are all better options and none are available from the Big Boxes.
It's not uncommon for contractors to push less expensive brands as better than they are. It leaves more money on the table for them.
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