I ordered the lamp after all the positive reviews. The manufacturer also promises 5 years guarantee, unfortunately my already after 5 days (depending 10min commute) was defective. The lamp has flickering or no longer went out. The light is sufficient for cycling to more I am not come. Even if I can exchange the lamp arise but additional efforts. In addition, should watching the price potential buyers, it varies greatly.
Addendum: For some reason, the lamp works again. Batteries and out, shaken once or twice - going.