I think they changed the design of these shoes, because the first ones I purchased had like, gel heels and were AMAZING.  But I work in an office in the city (working up to 18 hour days) and I wore these everyday all day.  They are more casual, not as chic, BUT the most comfortable work shoe I have found.  I have bought them in black 3 times, and brown twice because I have worn them out I wear them so much. The back is comfortable and doesn't dig into my heel, and I swear they have memory foam or something in the sole to make them squishy.  Love.