Well, they did get back to me. It sounds like the same impossible to clean texture that's on the acrylic tubs and shower pans I've seen. AS said that's mandatory now.

I wonder if Kohler's slip resistance method is less ugly?

Our Toto cast iron tubs and Kohler cast iron shower receptor (shower pan) all have no-slip grips--that was non-negotiable as far as we were concerned. They are not uncomfortable to sit or stand on (more like extra-fine sandpaper texture, not coarse at all), but should provide enough traction to prevent slipping.

I clean our tubs using Lysol Basin, Tub, and Tile aerosol spray/foam cleanser (I use 7th Generation Disinfecting Bathroom cleaner on the walls and in the shower pan in the guest bathroom; minimizes the likelihood of getting the Lysol product on the travertine floor tiles since it can etch). Occasionally the no-slip grips still look less than pure white after cleaning (happens more often in the summer when we're barefoot more often--grimier feet=grimier tub floor). Then I use a dampened Magic Eraser--buff over the tub (or shower) floor, rinse, and the grips/tub/shower pan look brand new.