we had both stainmaster & 80/20 wool twist in our house. nylon in bedrooms, wool in living.
I will never, ever have nylon in my house again, no matter what the marketers call it. It did not stand up to wear & tear & that was just the bedrooms.
However after 10 years, the 80/20 looked as good as the day we had it laid. I will nver have anything else in my home again.