These shoes are super light and comfortable, like a slipper.  They provide little or no support and little foot strike cushioning, but I think the idea is to promote the natural "barefoot" running style of mid-foot rather than heel strike and to develop the foot's natural shock absorbing capability rather than to get that from the shoe and the resulting unnatural style of running.  But, I'm not a scientist.  I just like the way the shoes feel.  I run in them about a half dozen times now.  Seem reasonably durable.