The easytone renew shoes are comfortable, but run very wide for a narrow foot.  I had a time pulling the laces tight enough to keep the shoes snuggly on my feet.  The heel does still slip some.  After just one wear, I could tell that additional muscles were being used - I had a pair of these years ago & am convinced they help tone you.  The only negative is that they look very big & bulky & run wide, especially on a narrow foot.