Alox is tops; too bad it's only available on a handful of models.
Nylon is highly underrated; it hides wear better than red Alox, or translucent or cellidor. And it's just rough enough to provide the second-best grip security, right behind Alox.
Both the original cellidor and newer translucent scales look great when new, but soon show wear; oddly, though, once they get worn all over, they have a sort of silky look that's actually very attractive. The worn ones are a bit less slick, too; but the fresh scales are the slipperiest in sweaty hands.