IMO, these are fine, there is a slight feel difference. A good option for someone not wanting to restore but preserve. I have played them on classic SS titles and new games. They feel fine. No harm in using one. I see no reason to overreact one way or the other.
Cliffys are fine too, they do a great job preventing wear on high traffic areas, easy to install and relatively inexpensive. There is a reason Cliff is often weeks behind on his orders, he makes a great product.