Drinks labeled "Zero Sugar" and "Sugar Free" have minimal sugar compared to the original variety of the drink.

The "Zero Sugar" type tries to mimic the flavor of the original as closely as possible. The "Sugar Free" type is generally its own flavor profile. This extends to diet and zero sugar sodas too, where diet (like Diet Pepsi) is its own unique flavor and the zero sugar (like Pepsi Zero) is a low-calorie replica of the original drink's flavor.

Please do not ask me what the Pepsi Max is, I do not know.