This is the first pair of Birkenstocks I have owned - and it won't be the last. The sort footbed was appealing to me.  I was advised (by a Birkenstock lover)to start with short wearing and increase the amount of time worn until my feet got used to the footbed.  I wore them for about three hours the first time and I realized what my friend was talking about. It was too long.  My arch hurt.  She assured me I would get used to them if I started slow, adding time to each wearing - and then I could wear them all day without a problem. She was right.  I have flat, pronated feet that require support.  These sandals seem to work well.