I have always been a Asics GT 2150 girl. I swear by those shoes so when choosing these I was skeptical. Why fix it if it aint broke right? Glad I decided to change. I took my new Kayanos for a run and loved the feeling. They gave great support and every heel strike I felt no pain and was like running on the Temperpedic foam material. I also had less leg fatigue. There was no "break in period" they felt just perfect. I average 5 miles a day 4-5 times a week so these shoes have met their purpose.