At their core, mayo and Miracle Whip are similar. There are a few compositional differences, and when you try them, you'll form an opinion about their taste.
They're interchangeable in most recipes, per Taste of Home. As with wine, use one you like.
Miracle Whip has less fat and calories than mayo but refined additives, making mayo a healthier choice
Best to make your own mayo with egg yolks, oil, and acids (the less inflammatory the oil, the better, per Healthline).
Whatever you use in your sandwich recipes, if you have company, know which side they'll be eating on.
How Stuff Works says mayonnaise is an emulsion of egg yolks, oil, acid (usually lemon juice or vinegar), and seasonings.