When you roast your coffee at a high temperature, the coffee will roast much more quickly. A quick roast will allow the entire flavor compound of the bean to become more pronounced. This means that nutty, chocolaty, fruity, and berry flavors will taste more full in each sip of coffee.
A shorter roast period at a lower temperature results in a smoother, more complex flavor that actually tastes fresher for longer. High altitude roasting results in the smoothest, freshest roast—and therefore results in the best coffee.