This is the first light I have ever owned for my bike, and I couldn't be happier with it. I bought it for a night relay I'll be participating in later in the season. I haven't used it on the trails yet, but I have used it on the street to commute home from work. I get out at 12:30am and most of the route home is pitch black. I could see everything with this light; even on the lower beam settings. The handlebar mount is very secure, and has yet to move at all during my commutes. It comes with a helmet mount as well, but I have not used that yet. For the relay, I'll need to have a secondary light source... I will be buying another one of these lights for use on my helmet. Awesome light!
Edit... Spoke with a guy I work with tonight who passed me the other night going the opposite direction. Not only did he say the light blinded him, but compared it to a HID light from a car. I told him the light wasn't even on the brightest setting :]