We have a Diamond smart 7 foot table for 6 years now in our poolroom and have never had a problem with scuff marks on the balls from the pocket liners or from the ball return system. It’s the dark gray stained legs, cabinet, aprons and rails, with the black leather pocket liners.
At first I was reluctant to ever use my highest quality set of pool balls with this table due to the ball return, but I’ve not seen any scratches or wear on the balls as a result of playing with these balls on this table.