We've been using Kraft Real Mayo in our deli for 26 years and it hands down, bests the other brand of mayo. While it doesn't have anything to do with taste and binding quality for blended salad sandwiches, the fact that Kraft Mayo has a built in handle, makes it much easier to use in Foodservice situations.
Sam's price is competitive as well making this an easy choice.
*Although safety is always taken to seal and bag each individual gallon of mayo for shipping, strangely, that's where the effort ends. The box they arrive in is typically twice the size needed for delivery and the gallon jars are usually in complete disarray when they arrive (see photo).