I had never heard of these, but after looking them up, I don't really get it.
The first testimonial on the website is about how the person's legs were sore after wearing them for a few days. They use that as a good thing to show that they are giving you a workout. So I can understand buying them for non-disney use to work your leg muscles and burn more calories.
But walking around disney is tiring enough as it is, so why would you want to wear shoes that make your legs work harder?
Where do they sell the Disney ones?
I bought a pair of the Mickey ones at the Poly in March. I wore them a little on the trip but they do take some getting used to. Now I can't live without them they are the most comfortable flips I've ever had . Try them. I love the polka dots and the Mickey on the strap.
They had them at the gift shop at the Contemporary but I purchased them at the huge gift shop at Epcot (in Future World in front of Test Track,Mouse gear? maybe). They also had them in brown.