Sorry for my english. I've a system with Sonof Mini (Wiring 3-way Insteon Switches) with the wire connected outside the house .
Everything works for some time (10 days) but then the Sonoff fails (broken). I've already broken two.
The suspicion is that Sonoff's input is sensitive to noise and a storm is enough to spoil the device.
Another Sonoff Mini with less cable and inside the house has no problems.