The ingredient list on the sandwich label doesn't leave a lot of room for secret ingredients; it's just cheese (american and swiss), cream, emulsifiers, lactic acid and pimento, plus the white bread and mayonnaise.
Matters of taste are not debatable: they just exist.
There are many gradations of white sandwich bread, though. There is little beneath Wonder Bread, but that space does exist. Above it: some store brands, Pepperidge Farm, and then some ways up, Arnold's Country White (which is itself at the bottom of Arnold's pale offerings: the Italian is a nice step up, and then their Sourdough, while not holding a candle to a fresh-baked loaf from any reasonable establishment, exceeds that by far).
Other parts of the US may have their own challengers at any step of the ladder.
I'm not familiar with Arnold or his various bread varieties, but sourdough is certainly not what I mean when I say "white bread". Neither is French bread, nor challah, nor any other reasonably flavorful bread made with white flour. The sandwiches under discussion are made with Wonder Bread or something much like it. It is that questionable taste that astounds me.
