DH got blisters from his tennis shoes but he has tender feet that are soft as a baby's!
My kids wore Keen's and were absolutely fine. When we were complaining about our feet, they chimed in that theirs didn't hurt at all! Next time we go, I plan to get me some Keen's along with some new Malindi Crocs. My feet never hurt when I wear the Crocs.
I NEVER get blisters on my feet. Maybe those ugly callouses on my feet (from always going barefoot) are good for something! When we were at WDW, I rotated flip flops (which I absolutely flattened from walking so much at WDW) and Clark's sandals.
I was shocked when I got blisters at WDW. I was too tired to really think straight about it at the time and I had an eye infection so maybe I wasn't seeing too well, either.

But, my blisters weren't from shoes. There were small blisters all over my feet mostly in places my shoes didn't touch like the sides of my feet. My blisters were from something called the Disney rash that I only heard about after we'd come back from our trip. It is from a combination of heat and chemicals in the asphalt and you can Google it. Next time, I plan to wear something protective like sunblock on my feet and the bottom of my legs.
My feet hurt so much that I couldn't wear my tennis shoes. At the end of the trip I actually wore some old Crocs I had brought for my DH to wear to the pool. It was like I could hear my feet sighing with relief.