These shoes are extremely good. Great arch support. Great Stability. This is the 4th pair of gel kayano's I've had (16, 18, and 2 pairs of 20's), However. Both of my 20's that have the sock lining that's really soft, and both pairs have ripped on the inside at the heel. I wear them almost exclusively with Balega running socks and they have Nathan lock laces that I keep as tight as is comfortable. I don't notice any heel slippage that is causing the tearing of the inner lining. Once it tears, the shoe loses a noticeable amount of stability since your heel isn't held as well and can result in the material bunching up.