I have the EMS PT50C also and also use it at my home base. Even with reliable utility power and without old campground wiring, my EMS has shut down my power a couple of times in the past two years.
It is definitely peace of mind. I always know when the power has been off since my microwave clock is off. Then I can go look at my PT50C to see why it was off. Of course if the power went off completely from the utility there will be no indication of the fault.
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch
2010 Jayco Designer 35RLTS, Cummins/Onan RV QG 5500 EVAP, Progressive Industries EMS-PT50C, TST Systems 507 TPMS, RV Flex Armor Roof