Pete,
I have used super C panniers for the last 6 years.
I am not a world tourist, only week tours and day rides in the UK, plus shopping every other day.
Maximum load carried in the 4 panniers 30Kg
The panniers are waterproof and my short tours have all been very wet at times. The last 6 summers in the UK have been very poor for warm sunny weather. The canvas material gets wet to touch but the insides and contents are dry.
I reproofed them once with Carradice wax, not sure if that was needed but it was an interesting job. After waxing the panniers definitely picked up wind blown dust a lot easier.
I wore a hole in one with the end of a U lock poking through, easily fixed with McNett SeamGrip to the rescue.
I found the super C hooks a bit difficult to fasten and unfasten in cold weather. That plus the hooks not really fitting the front of the Thorn low loader made me retrofit Arkel Cam Hooks. I find these a lot easier to load and unload from the bike.
I have a son with the same rear panniers set up and he is very satisfied with them.
What else would you like to know?
Julian.