I used to own a PF-9 that was truly unpleasant to shoot. I used a Hogue with it, but didn't like the way it shifted on the grip and changed the grip's profile. The Talon grips won't add "cushion" the way a Hogue will, but they almost become a part of the grip, doesn't change its profile, tames any abrasive surfaces and allows better purchase on the firearm. I believe the combination of all that helps reduce the perceived recoil, but then again, I never thought the Nano's recoil was harsh in the first place. I've never tried the sandpaper version, so I won't comment.
BTW, I have Traction grips on a TCP because I don't think they make Talons for it. I like the one-piece design of the Talons better, but they are a little less expensive and help too.