Mayo is fine on a dressed up burger. Y'know with lettuce, tomato and onion.
With that said, I just had a reheated burger from last nights grilling. It already had pepperjack cheese on it - all I added was a few healthy splashes of hot sauce.on the roll.
I prefer my dogs and burgers plain,'cept for 1 or 2 slices of American cheese on my burger. All of that other junk just distracts from the taste of the beef.