Tested: Since 8 Oct. 2013
This lamp is not available as a dynamo taillamp. It could be a good dynamo lamp! I like how it looks and the optics look quite good as well, no blinding of trailing cyclists, the light is distributed very well over a larger area which is the ring around the LEDs but the LEDs light up a bit in the middle too (and not as a point source!). The light at close range can be annoying to some (I asked someone else to judge it too), so better distribution over a bigger surface is still what we need. There is a section of light in the beam that is nearly collimated (so a tight beam) which will give good long distance visibility. The rubber cap on micro-USB port is a bit hard to get off but even more difficult to get back in, but I suppose that means it will be waterproof there :) The mounting method is by rubber band which Sigma thinks is cool for bike computers and lamps, but which in reality sucks harder than a black hole. The on-off switch is not as good as on the Lightring, in particular because of key-bounce (result: light going off immediately after pressing on, or not going off when it's on) and you need to press it too hard.
The included batteries are of the low self discharge type, charged and ready to use when you buy the lamp.
Verdict: Fairly good, in optics it trails the Philips lamps, total package with rechargeable batteries is nicer.
