I did not agree on the exchange the material on the belt of Amadeus, but after more than two years and I realize that I know this turntable belts with monofilament polyester, nylon thread I experienced the same size:
1) the nylon handles better - I prefer a loop knot to double knot

2) by sliding it between the fingers, it is less rough polyester.
3) non-twist
4) more resistant to tearing
5) seems to be more elastic
It 's just one day that I installed the nylon and I have yet to assess whether there are changes in pitch, durability and noise
By the time we'll see ...