Which one better?
I am very perplexed, this seems like a very debatable topic. Food often is a subjective choice and a lot boils down to adaptation, climate, and nostalgia. Both of these snack items are built from items that are found in almost every household. The fact that french fries are a single ingredient dish while onion rings require you to create a batter, could be a differentiating factor when it comes to choosing one of the two, but then again it's not just about the number of ingredients. Potatoes are comparatively a more comforting food when compared to onion rings. Potato as an ingredient is more enriched with potassium compared to an onion, for that very reason, I would give french fries the upper hand.