I only really notice the degraded resolution with the big live events or if someone is hogging the line/downloading something big on the 2MB ADSL line I am using.
But yea, people were complaining quite a bit that the rugby match of Sunday was low(er) quality over DSTV Now. As per DSTV it is a common problem worldwide with these big live events - while the rest of the world has been streaming live fullhd events, with much bigger audiences, without a problem. Obvious passing of the buck. But I do not know the technical details of what is (or is not) going on there.
Not much you can go about this. Make sure your line is not being hogged while trying to stream something important?