Why are you testing an update from an established studio? That's their responsibility.
GOG are pretty careful about what they upload. They like to know exactly what they're uploading I guess. You complained about inferior service because you get the patch later, but really, which store is actually putting more effort into service? The one that automatically pushes updates immediately as soon as they receive them or the one that has people who test the updates? Which actually has a higher level of service
? Writing a computer program that pushes updates is a lot cheaper in the long run than paying people to test things.
I don't think it's anything more than a waste of resources to make your customers wait longer for a patch that's released by an established studio like Double Fine so you can "double-check" it or whatever.
So, to answer your question: Steam is the better provider in this case. "GOG is testing Double Fine's patch" is terrible service.