We had a pair of wireless for about a year. This was good because on a coupled bike it's one less thing to undo and redo. But I finally got fed up with the flakiness of the wireless systems. You get to have batteries both in the transmitter and the head, and if you lose signal is it because the sensor got bumped - and is no longer close enough to the magnet? or is it because the transmitter battery is getting a little weak? or perhaps the receiver battery is just weak enough that it's not picking up, even though it can drive the display. So I put a wired on the front, and we still have the original wireless on the back. Keep in mind that we ride year round (had to fix a broken chain yesterday at -10C), and batteries have less ability to produce power for a given charge level as the temperature drops.

Yes you can get cadence transmitted wirelessly to the stoker bars. In fact, the wheel magnet is further away, and it reaches. There is a smaller selection out there that will transmit with enough range to give cadence to the captain. Stoker says she no longer needs cadence.