These shoes are ugly as sin but they are sooo comfortable. Actually, with the right clothes they can look quite cute in a mori kind of way. I have flat feet with corresponding overpronation and the problems that result from that (sore knees, lower back etc), but the arch support in these clogs really help with these problems and I don't experience discomfort even after standing and walking for a long time. I was not sure that I'd ordered the right size because they felt quite loose but this, I believe, is the way they are supposed to fit (according to the Birkenstock website anyways). I wear them with thick socks and have become used to the way they slip a bit on the heel... it's very unrestricting which is good.
So, they may not be the prettiest shoes in my closet but they are certainly the most comfortable and beneficial to my overall foot health. My feet thank me for buying them.