I used to wear Mephistos and loved them, usually I wore the sandals (about 20 years ago). They had a footbed much like Birkis and cost $120.00 back then. Lasted forever, provided good support and looked great.
I'd think about buying an enclosed Mephisto but can no longer wear the mules (without a back) since I accidently kicked off a mule starting down the stairs and fell in 2010....
Mephisto is an excellent product but yes, expensive .... 
*~"Never eat more than you can lift......" Miss Piggy~*