I like mayo on sandwiches and as a salad/dressing base...
I prefer Duke's for most uses, if I'm not making it myself... but sometimes Kewpie is what's needed. (They're basically opposite versions of mayo--Duke's is tangy and has no sugar, while Kewpie is mellow and a little sweet.)
These days, tho, I generally make my own vegan oil-free mayo from tofu and cashews... and don't use it that often.