What is the difference between the different kinds of heirloom tomatos?
I have seen the so-called Ugly tomatoes called heirloom. I have also seen orange colored and yellow colored tomatoes being called heirloom. I recall eating some nicely shaped heirlooms a while ago but now they don't sell those anymore. How true "heirloomy" are the ugly tomatoes? If so are there geographical varieties that are better than others?