Our robot's omniwheels (6" diam) last year (pic uploaded below) were awesoem on carpeting but are not good on steel as they've got aluminum and lexan
Our 9" omniwheels this year came in today. Though not as pleasing to the eye as last year's, they're lighter and the treads are made of a very sticky urethane that can go up the mesh easily with our two other 9" wheels which aren't omnis.