I echo TrojanHorse's words. I just started night time MTB riding with some friends. They gave me this light to ride (l#1 link below) along with the replacement (longer run time I'm assuming) battery (link #2 ). These guys swear by these things. I have a Light & Motion, and figured I'd save for back up when the battery pack burned down. Well, 2 1/2 hours later I still had TONS of light and it was still shining bright. I just placed and order for each a few days ago.
1. http://www.amazon.com/dp/B00F372RGK/...332200_TE_item
2. Robot Check