I have problem feet (hallux rigidus and plantar fascitis) and can only wear rebuilt customized shoes OR MBTs.  I ordered these in 1 size larger because the other reviewers said they ran small and I wanted to be able to wear them for walking in winter with a thick sock (and my orthotics).  They are incredibly comfortable and getting the size larger was right on, but I find my heel tends to ride up in them (with or without the orthotic).  Also agree with the other reviewers that the closure device is a bit fussy.  I'm not sure yet whether to keep or return so giving them 4 stars because of the heel problem.