I tried them on Saturday, and again this morning to make sure I was right the first time. The heel box is so big these shoes slip right off my heel like a pair of bedroom slippers. The shoes are excellent quality, very light at 1 pound, and they float. The problem with the heel slipping out is a non-starter though. I'm glad I tried these in the store before buying. I wish they would fit and stay put, they are really nice shoes.
I gave them a 10 for quality and design and a 0 for not staying on my feet. Average 5. Another thing I noticed is the sizing. I usually take a 11 or 12 but these shoes I fit a 9 and almost fit an 8. So I would say adjust at least 2 sizes smaller than your normal footwear.