I love my Birkenstocks, but I have to share my Disney experience. I wore them during a June trip and got caught in one of the flash downpours that are common in the summer. It flooded in front of the MK and we had to wade through knee deep water to get from the monorail to the bus area (we were actually coming from Chef Mickey's on the monorail to get to the MK to get to a bus back to our resort).
By the time we got back to the bus, the tops of my feet were rubbed raw from the wet leather. I had to wear socks and tennis shoes the rest of the trip... and then it rained again and wet tennis shoes were even worse than the wet Birkenstocks.
I like Tevas for disney now. If they get wet, they may chafe, but they're not going to literally tear up my skin the way the Birkenstock leather did.