Specs are a little misleading. It cannot sustain maximum brightness for more than about 2 minutes before thermal regulation kicks in and light output drops to around 4000 lumens, and then continues dropping to around 2000 lumens as the pack discharges. This is still a bright light, but there's only so much you can do in that "soda can" size. Also, the battery pack is proprietary. The Candlepower Forums review also mentions noticeable electronic whine and noticeable (1khz) PWM strobing. All in all still an impressive and very bright light, but at this price point I'd consider the other options carefully.