These are the exact words from backpackinglight.com concerning the EOS (older, 1W version)...

"The EOS had an output of 40 lux after three days (72 hours) on low with alkaline batteries at 70 °F. We found we could still perform chores and follow a clear path at this output, but after another ten hours output dropped to roughly 10 lux and remained there through day 9 (216 hours). 10 lux is very minimal light, but still useful with night-conditioned eyes for certain simple chores." Here's the url: http://www.backpackinglight.com/cgi-bin/backpackinglight/princeton_tec_eos_headlamp_review.html

According to Princeton Tec, this is how they calculate burn times: "Burn time is the total time that the headlamp produces a minimum of 0.25 lux at 2 meters. 0.25 lux is about the equivalent of a full moon on a clear night. Regulated burn time is less than overall burn time." The interesting thing here is that a full moon on a clear night is 0.25 lux. I've hiked many nights using only the moon as my light source when it's full. Ten lux is definitely usable light.

Personally, I would like to see an unbiased test on the Fenix, Zebra, and all other similar lights before I take the specs they give as gospel. Often these numbers are exaggerated for marketing purposes. In my opinion, the best way to determine output is to get in a dark room and compare each light. This is always very illuminating:). I also find it hard to believe that this light, using 1AAA battery, is putting out 75 lumens, especially for an hour! If you were to ask the Princeton Tec guys, they would definitely call your bluff! According to them, the Cree and Rebel LEDs used by the Fenix and EOS are rated to 80 lumens in a lab pushed to their limit, and put out this light only for a few seconds. They are also using much more wattage than the 1.5W that a single AAA battery can produce.

I do believe there are some very good lights out there and this market is incredibly competitive. I've checked out the Fenix and Zebra lights. They are quality for sure. I own a SureFire flashlight (L1) and am amazed every time I turn it on.

I used the new EOS Rebel Bike last night and can't believe the amount of light coming from it compared the the older version. LED technology is really improving and that is good for everyone. I know Princeton Tec is doing everything it can, the best they can, using the materials they feel meet their high standards, to keep up with this technology.