I have the single and it is bright enough for my uses - though, as I live and commute in the city, I am generally in pretty well lit areas even after dark. I do go through a park with no street lights I've never had any problems. It's a lot brighter than our old one that was not LED. I also like that the light is very white - not blue like the early LED lgihts. The blue ones make every thing look very flat - it really messes with your depth perception.

For city riding I don't actually like the really bright lights (like HID lights) - they may be good for trail riding at night, but they blind other riders and drivers on the road....