Wasn't expecting the thicker inner surface to make this much difference, but the sensation is noticeably bolder than the softer versions. The bolder edges are a nice touch too, firm but not harsh.
The firmer elastomer really does make a difference, the thicker inner walls give a much stronger sensation than the softer ones I've tried. The bolder edges add a nice bit of texture too. Wasn't expecting this much variety in one pack.