My nana bought these shoes after they first came out, and still wears them daily.  She found a pair for me, and though i don't wear them daily, they'yre comfortable and don't cause me discomfort.  Walking downhill or down stairs feels a bit off and takes some concetration, as you feel like you're going to fall forward, but no cimplaints really!  Oh, and the toning muscles part is total hogwash.  If you're buying the shoes just for that reason, you'll be disappointed.