Well, I disagree. The difference in image quality is always there, even at low magnifications - ED/Apo/whatever scopes always have a cleaner, more detailed and more contrasty image than their conventional counterparts. This is true for the Nikon scopes, the Leicas and the Svarowskis, and also for the Minox. I never used a Minox in the field, but I've been looking through them at a trade fair over here, and I found the difference was quite obvious.
Hermann