FWIW2, the Icon only runs at 1.7W. BD advertises a 3W LED, but doesn't mention that they do not run it at full power. (The plastic-covered heatsinks are inadequate to run the LED at full power. It would overheat and burn out. Look at an Apex to see what "real" 3W heatsinks look like.) IMO, this is misleading advertising by BD.
FWIW3, on my road bike, I use a 1W narrow beam aimed in the distance, a 3W broader beam for the middle distance and surround, and a 1W light aimed down at the ground (to spot sticks etc) on my handlebars and an Aurora hiking light on my helmet (to stare down cars and light my instruments and view direction). (I often ride on a very dark bike path where nearly invisible pedestrians in dark clothing are a major hazard.) A mountain biker is likely to want a brighter wider pattern.
Doug