I really love these shoes, but they are definitely not for every one. Previously I was
running (about 20-25 miles a week) in the GT 2170 which are great, support oriented shoes but are a little wider in the toe box than past
Asics shoes, and the colors are pretty boring. However they have great cushioning and super solid support. I decided to pony up top dollar and try the Kayano, more out of vanity than anything else (the black/yellow looks awesome). The first time I ran in them I immediately noticed a couple of big differences. They are much narrower in the forefoot, so much so that unless you have slightly narrow feet like mine they may be too tight. Luckily for me they fit perfectly. I also think they have a lot less support than typical support oriented shoes, especially one like the GT 2170. In truth they feel much more like a neutral shoe with just a touch of support. Again, this works for me (I am not a big guy), but if you need a lot of support I doubt that you will be happy with these shoes. Like the GT they have terrific cushioning, which is really nice for long runs. But it feels a little lighter and sleeker which means that it can handle faster paces without feeling clunky. So, as I mentioned before, I really love these shoes. In fact the second time I wore them I ran a half marathon and set a personal best. So overall these are great shoes for runners with average to narrow feet who need a well-cushioned, long distance trainer with just a touch of support. If you have wider feet or need more support I think you will be happier with the GT 2170.