This roast color is where good things begin to happen. Balance between acidity and flavor, fruity nuance, lively mouth feel, and long finish all are achievable at the true light roast. When purchasing a single origin coffee, the great ones are best at this roast color.
They are very forward on your palate, because the carmelized sugars are at their highest level and because the roasting process has not yet begun to burn the vegetable matter. Thus, if you are looking for differences between the coffee from one country or region and one from another region, taste them in their light roast form, for that is where the differences show up best and most clearly.