Actually in a generic sense, ethanol is less corrosive than methanol. The Aquamist simply has some components ( I believe seals) that are less tolerant of ethanol than they are of methanol. Rubber and other elastomers have different tolerences for the various alcohols. Each seal material will swell a small amount with each type of alcohol, some more than others. If a material swells enough with one alcohol that it is not recommended, it may be perfectly safe with a different alcohol.
Methanol has a higher oxygen content and latent heat of evaporation than ethanol, but ethanol has other advantages, such as lower toxicity (important in submarines) higher energy of combustion / pound, etc. so in practice they are very nearly identical as far as performance is concerned. One of the reasons the military settled on methanol in aircraft, was to keep the GI's from diverting it to other uses
In the pacific theater, the high test ethanol used in U.S. Navy torpedos frequently ended up being used for "pseudo medicinal uses". The gyros on the torpedos were cleaned with high grade pure ethanol. It was also used as the fuel in Mark 14 and 15 torpedos in their hybrid compressed air alcohol propulsion system.
This ethanol was called "torpedo juice" and also ended up being used for WI systems on the fighter aircraft, when methanol was in short supply (which was common in the early years of WWII). WI is called ADI in the aircraft industry.
In the early days aircraft mechanics would use deicing alcohol which was isopropyl alcohol. This alcohol was not compatible with the ADI metering settings and resulted in blown engines. The word came down from Pratt & Whitney to use only methanol or ethanol in the ADI systems.
Larry