Assembly:
With enclosed assembly instructions made quite quickly. Only the cable connection via open cable connectors lying on the lamp housing and the appropriate cable lugs works, but does not make the most stable impression and I can imagine that still can be problems with prolonged use and bad weather.
The connection of a USB cable is something frimelig and the handlebar switch, I think when you connect firmly ever since the connection is quite stiff. However, in this way probably ensured that the USB cable does not slip when bumpy ride.
The Light:
I fell right on the incredibly good illumination of light. Man has the right and left sufficient light to the sides. The light and illumination are compared to my previous Cyo RT senso plus significantly better and more evenly.
You should try it yourself, the "reference images" on the website of Busch & Müller convey a false impression (even smoother and brighter than real)
I have the lamp set relatively high and can see incredibly far in the dark deserted and unlit forest trails. In the city I set the lamp bit lower so as not to blind oncoming traffic, but then the light / dark boundary is very hard.
Processing:
Unfortunately, the lamp housing together with the lamp glass from plastic. I am skeptical whether the lamp glass remains scratch-free. Especially in the current season accumulates quite like dirt on the lamp glass and I remove this carefully, just to the potentially sensitive lamp glass not to scratch. But that it is easily scratched "only" a guess here must show the time if my guess is right;)
USB charging
I have tested the charging function once with a Nexus 5 and had no problems. For me, the charging function was permanently available. Once USB charging power is available, a small red LED on the handlebar button will light up. I would have found more intuitive here a green LED, but that's just a "blemish".
In my test drive, I drove about 30 minutes with an average speed of 23 km / h, the display was consistently turned and ran in the background, the GPS-tracking app Endomondo. Before the first run I had 63% battery capacity and 74% after.
In another bike ride in the mountains I could see that about 15km / h are needed so that the buffer battery and even USB devices can be charged. If you drive a while below this speed, which. Occurs for example during long climbs, then USB charging is turned off and re-activate only when the speed is again some time over 15 km / h.
For me, the charging function is superb and fully meets my expectations.
According to instructions to disable for optimal charging function the light, but I have not tested whether light and charging function can be used in parallel, without leading to restrictions (if the speed is high enough).
High beams
The high-beam function must be activated on the handlebar button on short pressure and is indicated by a blue light both on the lamp housing and the handlebar switch.
The term high beam is somewhat misleading, because further into the distance, it is not enough. The existing photograph is just a little brighter. In dark corners that is an advantage, but it is not a huge.
According to instructions of this high beam due to the capacity of the buffer battery and the increased energy needs for only a short (about 15 minutes) can be used, but I'm enabled high beam about two hours drive with an average speed of 23km / h, without it being disabled or it exposed.
Conclusion:
I am very satisfied and have found a perfect for me light is but a little overpriced.
The various functions (esp. The charging function) are very helpful and the most important thing, namely the light, is just awesome.