I mainly use Copags, Fournier, Gemaco Monte Carlos, and DESjGN setups in my games. The only fading I've ever experienced is with Copags, which starts after heavy use in 3-4 games.
Regarding DESjGN decks, I can't speak to the newer stock he uses, but I've used my Classic Cultures in many games over the last 2+ years without any fading whatsoever. They've probably been handled by 50-60 different people, shuffled thousands of times, and they show absolutely no signs of fading.
Their durability/longevity is top notch as far as I am concerned. Photo below is of an almost 3 year old deck that has been used dozens of times...
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