I used nothing but rubber lug soles in the past and thought they were ok until I bought my new Chota boots with felt soles. I will never go back to lug rubber. They help out so much on the slippery stuff. I've never had a problem with them getting "gummed up" or anything else. Great boots.....good soles. I imagine the metal cleats would be good for certain applications but after wearing these for 2 seasons, am very happy with them.
Happy Trails,
Dean