My hands love the feeling of Topre caps best <3
Which are PBT.
PBT 'caps don't go yellow like some ABS, though I suspect that the additives to ABS make it more resistant to that than the 18-year-old yellow keycaps you see on WYSE. PBT is harder than ABS, (and more brittle. It will shatter instead of deforming if you hit it with a hammer, this is not a recommended use, though.) and also much more resistant to corrosion, so it should not wear out very quick at all.
I really like PBT. I suspect the porosity affects the surface boundary layer of the textured mould, making the characteristic roughness different? This is jsut a theory, but it would explain why everyone likes PBT keytop's texture, but you can still make PBT smooth (Like the sides of Model M keycaps)