FT,
I have one on my head right now. This thing rocks!!!! I have a Tikka, a Tikka Plus, an Aurora, a PT Scout, a SL Septor, the Energizer 2 LED headlamp, and a multitude of other incan. headlamps but this thing has become my favorite.
Just compared output to my Tikka plus.....The Petzl unit is definitely brighter, but not twice as bright (2 LED's on the Tracer vs 4 LED's on the Tikka) I would say 30% brighter. But the Tracer wins hands down in the weight and bulk department. I'm a hardcore backpacker and a fanatic about saving weight and bulk in my pack so the Tracer will replace the Tikka on my next trip; it's more than adequate for reading and camp chores. It won't light up enough of the trail for night hiking but then again neither will the Tikka Plus.
And BTW the over the top of the head strap is completely unnecessary IMO. But the designers of this light acknowledged that fact by making it removable.
All that being said, I still think that an Arc AAA clipped to my hat's bill makes a darn good "headlamp".