Optics: The 1609 looks elegant, jdoch the numeral "2" is (for a quick look) represented some getting used to.
Installation: The installation is easy. However, there is a negative point here. In this day and age have a lot of people, bikes with front suspension. Their scope is, of course, greater than the normal fork. Unfortunately, the supplied mounting rubber does not fit it. Fortunately someone has thought at Sigma, unfortunately only half. One can instead also use cable ties which corresponding holes on the transmitter available. Unfortunately we have not finished it brought the cable ties (costs 1 cent!) Be packed. So if you have any lying around at home, must first suspend the assembly and drive to the nearest hardware store (because the heart laughs).
The make the settings is also very easy on the hand. Those who can not find his tire size in the table of the manual, may calculate these or simply looking at Wikipedia (There is a more complete table).
Function: Yes what to say as large. It works as it should. The number of functions is really great for the price. Almost back too much, but with time you will figure it out how often you where to press appears to me until the desired display. The temperature display is a nice feature, I had been in no Fahhrad speedometer.
That was my résumé after the first day on the long-term suitability I can say anything here.
Normally I'd give 5 stars, but the thing with the cable ties so I can not let go, so just. 4