I bought my LC100 from LP. In the beginning I had a few cases in which the light wouldn't turn on --> I removed the bulb and reinserted it and since then the light works great. Sometimes the light won't turn on after changing batteries that are not Duracell, but if I jiggle a little the batteries it works excellent.
A cool feature of the LC100 is its spectral range, which is cooler and extends to the UV range. I attach to the LC100 purple filters from several layers of Cellophane paper, or combinations of blue/purple semitransparent plastics (available from any "Office-depot", dossiers, etc.). It takes less than 5 minutes to cut with scissors. With these "filters" the beam turns into a pale, barely distinguishable purple. But, many creatures and critters (including corals, sponges, jellyfish etc.) turn alive with green, red and sometimes orange luminiscent colors from distances of up to several meters away. A different way of viewing night dives with a completely unusual light- Highly recommended...