I am in love with these shoes. I work in a giant warehouse walking on an average of 20 miles per day in a 10 hour shift. In the last six months these are the third pair of shoes that I purchased specifically for this job and all the walking that I do on hard cement floors. The first pair were $100+ Nike Air and were comfortable for about two weeks when the hard floors seemed to just take their toll on them, new inserts didn't even seem to help and I basically felt I had wasted $100. I decided to shop around and not spend so much if good shoes weren't even going to survive all this walking. I purchased some $45 Filas and actually got a couple good months out of them alone and then even extended that with new inserts. I wanted to find something that didn't have the breakdown that these shoes had without spending an arm and a leg. After a short search it came between the GravityDefyer and these Spira's. At $65 I went with these. (some vendors had the exact same shoes for much much more) I have had them almost three months now and feel very little difference than when I first wore them. The insides are intact, a little wear but no material rips or breakage yet like the other shoes had after a much shorter period. They breath very well also. I totally recommend them for anyone who does a lot of walking or has back issues. I have had lower back surgery and all the walking would remind me of that everyday. These shoes have not eliminated that completely but have made it a non issue. I have only found one drawback in these shoes, because of the metal springs in them they do set off the metal detectors where I work so if you work in a secure facility or go to the airport a lot you may need to reconsider these. I do plan to purchase another pair when these do wear out.