Agreed. Their low gain screen actually uses a ton of gain so it's texture is extremely pronounced to my eyes.DNP does make a higher gain screen with far less sparkling than the SI Black Diamond materials. I honestly don't think people realize the difference in sparkle between BD materials and other ambient light rejecting screens.
But the worst SI demo I ever saw was a higher gain screen for ambient light (higher than their 1.4 as I remember), at a show. (I seem to remember it was recommended for 3D in particular). The screen texture was so bad, like dirty speckly water over the screen, I literally had trouble trying to "see through it" to the image, in terms of being able to just take in the image.
But as usual, there are trade-offs everywhere in projection, SI offers some great solutions to some ambient light problems, and I'd never use my own criteria to judge another person's who may have different requirements and different sensitivities. (For instance, I was terribly allergic to the off-axis performance of the HP screens, but many HP users say "what are you talking about, that isn't an issue for me," so if they'd gone on what bothered me they wouldn't have chosen a screen they are ultimately super happy with. Which is why we always say here that, especially with screens, see them for yourself whenever possible).