Yes, I agree: Duke's is better than Hellman's/Best Foods. It began appearing around here a year or two ago; now it's carried by most stores. At least for now, it's about a dollar cheaper than Hellman's, I assume because it's trying to persuade people to switch. You conducted an admirably rigorous study.
I do not agree that "It's got TWANG". I would say that Miracle Whip has TWANG, along with a lot of corn syrup that makes it disgusting.
But you left out an important contender: Kewpie. Many people say it's fabulous. I don't know whether I would or not. I think it has a lot of sugar.
The only times I've eaten mayo made with olive oil is when I've made it myself. Which is to say rarely, for special French or Italian dishes. Not that making your own mayo is difficult; it's not. It's very easy. BUT you have to use it all in about a week...