I have used the Wahoo RPM cadence sensor on three bikes and it works just fine. I've used it both with bluetooth (cyclemeter) and Garmin Edge 1000. I have also used the Garmin units. I can find no practical difference between them in use. I added a Stages power meter to my road bike which supplies cadence. I can see no practical difference to that between the other sensors either.
That said, I'd buy the Wahoo sensors since they support both BT and ANT+. Garmin units only support ANT+. I am *so* happy to be done with the alignment issues on the old style magnet sensors.
J.