Feta is the one Greek cheese we all think we know–but the feta field is fiendishly complicated, resulting in a wide range of feta choices. To put it most simply for the taster/buyer: feta can be white, yellow-ish, hard, medium-hard, medium-soft, soft, creamy, salty, medium-salty, sour, medium-sour, hardly sour at all, bland, medium-intense in flavor, intensely sheepy-goaty. But how do you know which is which?