All of the fastfood chains based in united states have much better quality abroad.
There's wide variability within the US anyway. I've noticed that affluent suburbs tend to have great fast food, while urban and rural environments have awful fast food.
EDIT: I mean the restaurant chain, I'm not sure of the root beer itself.
Many other first-world countries (thinking of EU, etc.) have much stricter rules about food additives, etc. So the bread, for example, tastes significantly less cardboard-ey.