One of the main advantages offered by the Nyon is that no added sensors are needed as it already knows, cadence, wattage (yours and the bike's), elevation, position, speed and slope. The only add on sensor needed is a heart rate monitor. I think is it probably fair to say, at this point, that its primary weakness is mapping. Hopefully Bosch is aware of this and a future update will improve matters in this regard.
Its integration with the bike's systems, size, power supply, level of customization, automatic start and stop route recording, assembly of those segments into a complete ride with accurate time moving, automatic synch of all ride data using wifi upon arrival home and good user interface both on app and on pc browser still makes it one of the most useful cycle computers I know of.