It will depend on your foot. My mom wore her Croc Athens flip flops the whole time we were at WDW this past May and loved them. I wore mine 1/2 day and had to change into my Teva Mush flip flops I had brought along (just in case my Athens were uncomfortable). For the rest of the week I switched out between my Teva Mush flip flops, Reef flip flops, and Croc Beach. When I go back in Sept my Croc Athens flip flops are staying home. After 1/2 day they were causing a hot spot just beneath the big toes on both feet.
I also can't wear my Croc Niles at WDW. They cause a blister in the exact same spots the Athens do. Both the Niles and the Athens have a little ridge on the foot bed that runs just below my toes that is uncomfortable after more than a few hours. I do love both the Croc Niles and Athens to wear around here though.