Advantage: Easy to read.
Disadvantage: Easy to wear off.
Serious problem of AR coating is that all of them are fluorine-coated.
Thus durability of these coating is very and still poor.
Two or three years before, I`m not sure exactly, CITIZEN developed TOUGH AR coating.
The Result is marvelous, but they still keep secret about coating process.
If I can say my personal opinion, One surface coating is the best considering durability.
It`s not difficult to distinguish whether coated both side or one side.
If colour of Glass seems yellow or blue, it may have one surface coating.
Regards,
HIROTA, Masayuki