From the information I could gather on Candlepowerforums, the G2L has an initial lumen output of around 80 lumens, as the module heats up, the brightness is ramped down to around 65 lumens for extended burn times, since the Nitrolon body tends to retain heat, and heat is the enemy of LEDS, the output is ramped down to keep heat output in the safe range
estimated runtime is around 9 hours of decent, semi-regulated output, with a long 4 hour tail of dimming light to the 14 hour point
It's best to think of the L60 LED module as a shockproof, indestructible P60 module with no filament to burn out, it's not meant to be a retina-scorcher