I have a built in version of the Progressive unit. When I use my generators to power my A/C, I absolutely hate the thing, because it cuts power when the A/C tries to start, then the A/C won't start due to locked rotor stall, then the surge protector cuts power again.
The only way to get my generators to reliably run the A/C is to turn on my inverter and let the inverter start the A/C so it is up and running when the surge protector passes power. At that point, there's no "low voltage" as the A/C tries to start because it is already running.
Someday I will remove it and got for a portable unit.