Bread from the in-store bakeries tends to have a better taste than the prepackaged stuff. Fewer preservatives, and usually just enough sugar or honey to activate the yeast.
French, Italian and sourdough French seem to be less sweet than standard American white bread.
Read the ingredients and nutrition labels on the packages. The ingredients listed first have the highest volume, with the last ones having the lowest volume. The nutrition label also will tell you how a serving is defined (one slice or two) and the grams of sodium, fat, sugar, etc., per serving.
Not sure what kind of butter you purchased. I usually buy unsalted sweet cream butter, which most people use for baking. There is far too much sodium in the salted butter for my taste buds and body!