I have to say that I use the transmitter only Indoor, ie. On a roller trainer in combination with the chest strap and the phone Operate usually three Bluetooth devices together. Cadence transmitter, Brutstgurt and NFC Bluetooth headset and it works great on my Xperia Z Ultra. Many write of crashes or even problems with installing the wheel. Nothing I could find. Super easy to install. Hab still looking short in Google and found equal to a manual of runtastic that was slightly better reading than the enclosed. That's a bit meager.
Since the distance because of my thick tires was a bit far the sensor to the spokes, I have a magnetic whiteboard magnets simply on the enclosed geploppt. This worked great for me. Now the distance is minimum, and the display work.
Whether the annual subscription with runtastic is necessary or not, everyone must decide for themselves. I have it done if I also now need no longer necessarily see. Choose Yes only half ways as I go Indoor and thus do not need the entire track log. Can bitching about now and then missing positioning not leave. This sucks already. The app will always communicate with any social network, but you'd never need to confirm.
The overview in own account is very nice. You get everything rides, speed, heart rate, etc in different views displayed and can increase its performance (or may not) see. The calendar view animated already to adhere well to set goals.
Yet the motivation is high for me. Can recommend the station, despite all the criticism of runtastic.
Biggest gripe I find the lack of (or intentional) opening of the belt. He is in one piece and must always be imposed upon from above or below. Goes on still, but when you're sweating already ne wet slippery thing undress.