I hav been buying ASICS for 15 years and have always needed to buy  1/2 size larger than a regular shoe so as I have done before did the same- The shoe is very comfortable and lightweight perhaps a little to lightweight- After running for an hour on the treadmill my heals hurt like the devil never had this happen before. Looking at the shoe I can see the heel construction is not the same as in my previous Asics I think there is  less gel and less support so I am disappointed as these shoes were pricey- I am going to keep them for bike riding but plan to buy another pair an older model that has all that extra support for my foot-My old ASICS are too old and worn to keep  I had higher expectations all related to several previous purchases of the same brand running shoe