oh gosh but there's so different types of mustard... but mayo is such a good base for mixing sauces and egg salad wouldnt be the same without it. i gotta go with mayo, even tho i barely eat either condiment lol

mustard for sure!

Definitely mayo. Chicken salad, tuna salad, pimento cheese, dipping for my fries... I use a lot more mayo than I do mustard.

MAYO MAYO MAYOOOOOOO

BOTH.

Mayo. But I use mustard a lot too. Specifically Dill Mustard.

mayo, mustard is sour. both are ok

i like both but for different reasons, but mayo and mustard on a nice publix sub is soo good

mayo mayo mayo mayo mustard is a close second

mustard

This is an extremely tough one, bc I like them both and I usually like them together.

I'll give mayo superiority, since it can form the baseline of so many other sauces. It's versatile. Bonus points: Kewpie brand Japanese mayo. The touch of MSG changes everything.

I do love mustard too, though. A local brewery makes all kinds of beer-based mustards that are wonderful.

You get it!! I like mustard, but mayo is a staple. It's a base. It's a mixer. Any sandwich is dry without it. An important condiment.

Mayo solely for the variety it has as a base, mustard is lovely but not neutral enough for food lube and so on

I love Mayo! I prefer it for its utility in sauces, but I also prefer the flavor over mustard. I also prefer the foods that utilize it like chicken sandwiches, and yakisoba! Mustard is tasty, and I love honey mustard, but it's a very prominent ingredient.

i'll echo many others here and say mayo, based on it's versatility as a base

AYO, IT'S MAYO

There is only mustard.

100% mustard for me

I'd like to suggest a third contender: honey mustard.

Mustard.