I’m no pro runner, but I really like the feel of the sums sock. Equally love the aesthetic as it was probably my deciding factor for going for sums over other running socks. Only issue I’ve really had is I’m a size 10.5/11 with a wide foot and I’ve tried the size M which seemed to be too small and size L which initially is too big. It does vary for type of sock, with the all seasons being most like my description. The ascenders are slightly tighter and feel like maybe they could be sized down one but other than that I absolutely love them. The cushion deluxe are most likely my favourite pair as they are nice and stretchy an easy to put on my wide feet but equally have great padding and comfortability particularly when in the shoe. Would highly recommend sums to a friend