So far, in a field of three or four companies and seven or eight styles of lights, the Flea's are some of the best I've used. The USB charging works great though rather than the solar chargers or using a USB port on a computer, I use an iPhone charging block and USB extension cord. They're light weight and the strobe mode has a pause so they pulse rather than simply flash. Another feature of the helmet mount that is nice(tested at Big Basin) is that it can be switched from helmet to hat and the headlight is light enough to use on the bill of a cycling cap. I hope to test the solar chargers in more favorable conditions. The off the cuff testing has been pretty inconclusive so far. For touring it's not been an issue with other USB lights using a hacked solar rig made for charging car batteries. It's not an elegant little thing but it was essentially free(ish) and works even in less than ideal conditions, point being, with USB lights solar is always an option.
I have both early and late commutes in the dark, fog and occasional rain. At risk of being dramatic, I feel like my bike lights are at times a live or die piece of safety gear. In California they are also required by law when riding after dark and the authorities are none too shy about tickets for scofflaw cyclists.