When I went last February, I chose awful shoes. Or maybe I was just not used to being on my feet so much. I was in some serious pain, though. On day 3 or 4, I bought a pair of the Crocs Mickey flip flops. They helped get me through it.
However, over last summer, they were a back saver for me. I have spinal arthritis in my lumbar and c-spine both. For the summer, we did season passes to a small semi-local theme park. We did a LOT of walking, a lot of time on my feet, and my back rarely hurt at all if I wore my crocs.
Not sure if they're better than or even equal to the brands others have mentioned, as I've never tried them. However, they worked great for me when I started off wearing them before my feet were killing me.
After I got home from Disney, my feet hurt horrible for almost a week- instant pain the moment I got out of bed and stood on them.
It was pretty bad. I'm pretty sure I have plantar's faciatis, but never brought it up to my doctor. I am hoping to have much better shoes next time.
I did notice once I had the crocs, that my feet didn't hurt as bad if I switched out during the day from 1 to the other.