To be a good commercial variety, a plant must balance a number of factors, and to some degree it is a zero-sum game - plants only have access to so much energy and nutrition, and so great gains in one area almost always mean a loss elsewhere. A good zucchini, for instance, is a combination of factors like volume of production, rate of growth, uniformity of color and shape of fruit, disease resistance, and of course flavor. There are some relatively minor considerations as well - do the leaves grow upright so it's easier to see the fruit, or do they flop around? How spiny is the plant (and therefore, how uncomfortable will it be to harvest)? Finding the right balance is a challenge for the plant breeder as well as the farmer!
This year there are a couple of new varieties we've been really pleased with. One is the yellow zucchini "Golden Glory," which has been a stellar producer and impressed us with its gorgeous color and flavor. "Lovelock," the red summercrisp we've had the past few weeks, is a new lettuce for us this year that has a great flavor and has held up really well in the heat. We just harvested the very first "Sarah's Choice" cantaloupe, which had a better flavor than any melon we've grown so far. (That was an early one, but we should have melons for CSA within three weeks.)
Do you have a favorite vegetable variety? What is it? Why?