I just looked at my Kraft Mayo in the fridge and it has no sugar in it at all.
I don't know what Dukes tastes like because they just recently started selling it here but they're both made with soy oil.
I thought Dukes was from Louisiana.

To answer MickiSue's question -

We use 1/2 safflower oil and 1/2 olive oil.

Personally, I like the taste of the full olive mayo but other members of my household almost mutinied the last time I made it that way. Oy! So we compromised to 1/2 and 1/2.

I like making my own because 1) I know what's in it and 2) it's pretty dang easy and cheap to make! (And my kids LOVE to watch the magic as the mayo erupts from under the immersion blender in the jar. ;-) )

Anne