Yes, I tried the knock off Nibble Net for a temporary boarder - thank goodness it was temporary because by the time he left, three months later, the thing was toast. I think I got that one through Big D. And he was only getting dinner in the net.
My hardest keeper actually prefers to eat hay from the Nibble Net and Porta Grazer vs hay that is loose on the ground. If it was causing too much soreness, I would think he would eat the loose hay first. When I watch him eat, he seems to relish the yanking part. It almost seems playful…
FWIW, none of mine have had any more soreness since switching to these nets - I had them worked on by a chiro for years prior to and after and yes some were prone to TMJ and certain sore spots, but no increase/change since using nets. One of mine even had to be switched to the smallest hole, I think 1.25" and she still empties it in two hours. The only one who seemed to struggle is the Haflinger because it seems like her lips are a bit thicker than the other horses so harder to maneuver into the holes, but she is an air fern anyway.