I've now got a range of SUMS socks - both the all Seasons and the Ascenders. Both are fantastic and I've run in both over a range of distances up to Ultra distances. I've found them to be comfortable and not had any problems with blisters etc. They've been comfortable.
The designs are varied and I love the range!
Customer service has also been great and I know the team are developing the website and order process to give more flexibility on subscriptions.