Go ahead and try them! They work very well for some and not as well for others. As an example, if I wear my crocs WITH socks I get a horrible rubbing, almost burning, pain on the bottoms of my feet, from the nubs of the crocs moving my socks around on my feet. So I pretty much have to wear them withOUT socks to be comfy all day. Everyone is different!
Try them, and if they work for you, try them at WDW!
Also, for me, I have to have a variety of shoes, at least two different kinds, to keep my feet happy.