Are WSOP versions any different from standard plastic copag cards in terms of feel, material etc... my experience with copag from before have been easy fading of index.
Feel and look the same to me. Bear in mind they switch them out fairly often. That being said, some of the cash games had decks that were in rotation for a while so there was some wear and marking that comes with play on the cards.
Personally love the feel of Copaq's and the way they glide across the speed cloth, but they are not among my favorites because of how quickly they fade. Unfortunately, they don't seem to care about how well the colors hold up.