If pushed I would probably opt for Ketchup although I do like a bit of Brown on my chips. I'm contrary, sometimes Tomato Sauce and Mayonaisse, other times Brown, sometimes neither or just with Mayo, but only on Crunchy Chips, not on the soggy chips from the Chippy.
Nah that's where you are wrong newbie. On crispy, thin chips there is nothing to beat Mayo (and maybe Ketchup) on your chips.
Or crispy-crunchy thick, curly chips or even wedges -mayo is the ****ing bizniz, if you cannot agree with that, you are nought but a perfect fool.
Sauce all depends on what your eating, eggs is definitely better with brown, most fry up stuff is better with brown. However Ketchup is better for things like Chips, Pizza, Burgers and Fish fingers. Mayonnaise is ok, but I'm not sure if choose it over Ketchup for chips