Often, what brand you were raised on will determine your mayo preference, although on occasion people have been known to switch. Raised in a strict Hellman's household, I'll never forget the first time I had a sandwich at a friend's house made with Miracle Whip. I actually gagged a little and couldn't finish it.
Which leads me to those who can't stand mayo no matter what brand it is. And then there are the Kraft aficionados and the Southern-raised Duke's loyalists. The Japanese mayo called Kewpie is gaining ground, too, while others will eat nothing but homemade. The debate is further complicated as mayo companies release new formulas and offer variations like 'Lite' or extra virgin olive oil.
(Images: Mayonnaise manufacturers)