How to compare Krah and ADS pipes?

In the South and North American pipe market there’s some confusion regarding the proper way to compare ADS pipes with other technologies. This is due, mainly, to the fact that ADS technology does not offer standardized pipe stiffness classes (for instance SN2, SN4, SN8, etc, as European standards demand), but they only offer one kind of pipe (with specific ring stiffness) for each diameter.