I must be odd, I like them both. Grew up with both in the fridge, Woman (my Mother) used to make mac salad and used both in it, she did tater salad also but not a big fan of tater salad.
I have come to making grilled cheese using mayo instead of butter. I am a butter of margarine person, trying to spread cold butter on bread is a nightmare, mayo works so much better.
There are some things i am not sure MW would work for, she used to make a couple different cakes that used mayo in them not sure MW would go so well in them.