Positives - Form factor, lens and brightness of the unit. It charges quickly and hold charge very well. Negatives - very sensitive to moisture, the 'double-click' lens is glitchy... It will sometimes unintentionally switches modes with even the most glancing of touches on the lens.
I use this lamp as a flashing light on my right fork-blade to make my bike for visible when commuting to work in the early morning or when going on night club rides. I charged it up via a USB and it works well, easy to attach to the fork blade and stays put (no sliding around). Overall a fairly simple light that works well and doesn't cause any trouble!