Great battery life, excellent visibility in the flash mode, and plenty of light for my local gravel trails. I haven't taken this on any single track or anything like that, but I imagine it would probably suffice for light (cautious) riding.
Great value overall though!
My wife bought a new bike that has the one-piece aero handlebarstem combination and the Garmin out-front dual mount for computer and headlight would not fit so the answer was to get a proprietary GPS mount and add the Lezyne 800XL for lighting purposes. The 800XL has several different modes (we use primarily the flashing mode for daytime safety) with varying degrees of brightness and seems to hold a charge to accommodate several rides before recharging. The rubber strap, although easy to remove from the handlebar for recharging the light, holds the light in position firmly while riding, even on chipseal or less than smooth pavement. The 800XL recharges quickly and vividly displays its state of charge via the color of the on-off button. An unusual feature is that when the 800XL is low on charge and on flashing mode, it converts to a lower powered steady mode in order for the rider to hopefully finish the ride with operational light. While the special edition 800XL comes in matte black or gold, the regular edition is available in several colors.