We do use the speedfun furious and no problems with the Bosch smart system so far. Of course, if you ride at high speed the range will be lower, as energy consumption grows in square with speed. But that´s just general physics, nothing to worry about ;)
It´s the app I was waiting for! My German "collleagues" have one too, but the price tag is a little bit disturbing, given the fact that you need an interface cable and basically three programs. Typical over-engineering ;)
I updated the firmware yesterday, just to realize that this app exists...