I got a pair last June and they work GREAT! We only went through a couple refills, but the level or EMPTY were right on. Had to replace the batteries in both units in January, but with battery readout with propane level no problem.
I use the Bluetooth on my Samsung Galaxy and we park our trailer at home, so I can check the level of the tanks from the house, so the transmit distance is real good.
It will be interesting when a lot of trailers get them as to how discrete the signals are.
Hope this helps
BobnRobin