Yeah, I had the Luxeon-based model, and actually used it as a helmet light, so I agree, that's one hefty light, it does rattle, and it can flicker. I gave it to my folks to replace their decrepit 2D Eveready plastic incandescent flashlight, and now my helmet sports the ubiquitous Fenix L2D Q5. Not enough throw for my tastes, but I haven't found any great 2AA throwers yet. Maybe I should just jump to 18650 and get one of the current crop of throw monsters...