Another happy user here. Paired with the Progressive surge protector, we have been "saved" several times. Being Thousand Trails members , we often find low electrical issues at their parks here in the West. The autoformer works every time.
I also monitor inside via a meter but I cannot stand there and watch the voltage meter all the time - I allow the autoformer/surge protectors to do their jobs. After about 6 years of flawless operation, the Frank's Autoformer has been well worth it!