feeling has more to do with texture, ie the surface characteristics of the mold, than the material. the major difference between pbt and and ABS is wear characteristics, and density and hardness. basically, if you are a very fast and hard typer, PBT will feel slightly different than ABS as you type very quickly with high force, but for most people, the major difference is in the texture imparted on the key by the mold and not the material used for the cap.