WE full timed travel every week/2 weeks for 7 yrs. LOTS of different places/different power sources.
Got a EMS-50A for just in case when we hit the road. It shutdown power a few times on HI Voltage (132V) and shut off power once on LO Voltage (104V).
I personally think the LO Voltage trip is too high....I get concerned when voltage goes below 108V. I monitor AC Voltage and swap to generator if below 108V
It has also found bad pedestal wiring problems when hooking up power on three occasions. Course a simple check with meter would have found them also.
It is one item that I could justify cost/risk/benefit.