Have been using one now for about three months. Great little device and about 40% of the cost of a Canon wireless adapter.
Couple of thing I found. It prefers the camera to be switched on and connected before the Camranger is switched on as it will not find the camera if the Camranger is switched on first.
When the battery gets low it can lose connection with the camera, although the green power LED is still lit and wireless connection enabled. This occurs with me after about 2½-3 hours use.
If you lose camera connection, you are better off restarting the the Camranger app ( On a MacBook) than trying the reconnect option in the app.
Small things and not really a problem. A second battery is also a good idea