The Food Guys, Jon Jackson and Greg Patent, review the results of a recent "butter tasting," discussing why butter's taste and texture varies so widely. The categories of sweet, salted, or cultured butter (a premium butter which has been flavored and is made in small batches) are just the beginning of the butter distinctions and vocabulary.
There's the ratio of butterfat to water, which matters in certain types of sauces and baking. What the dairy cows have been eating explains a lot.
And no matter what category of butter, it always pays to wrap it tightly and well before storing in the refrigerator or freezer, because butter is a champion absorber of flavors from aromatic foods nearby. Even the perfume worn by a passerby can show up in the flavor of butter that hasn't been wrapped well.