Thicker keycaps changes the density and mass of the keycap giving a different feeling. I like how thick doubleshot ABS caps feel. Just a personal preference thing.
Density or Rho = mass / volume.
So the caps' volume and mad can change right?
There is such a thing as too thick though.
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...... The biggest difference is the sound. ....
TBH I'm not sure I get the thickness thing being a component of feel. I'm currently using thick PBT caps on MX blues and there's no difference in feel between them, thin ABS (SP) and original cherry doubleshots, which are THICK. The biggest difference is the sound. To get a noticeable difference in feel I have to use a different switch on a different board (I've got blues, browns & blacks, also an ALPS board and had a Model M too).
When you factor in the resistance of the spring vs the actual weight difference between the different keycap types, probably about half a gram, it translates to approx 1-2% of the actuation force. The science is more complicated than that of course, because the spring's resistance isn't linear; but simply put, I don't think that an extra half gram of plastic on a 50g spring feels "different."
I still don't think that it's the increase in mass that's making the caps feel different - if SA caps "feel different" from OEM, surely it's because they're SA and not OEM, lol!
If anybody wanted to go down the route of comparing the feel of keycaps of varying mass, they'd have to use keycaps of exactly the same profile with the same texture etc. otherwise the results would be compromised IMO. I have tons of SA caps from a grab bag, the thickest and heaviest fookers I have ever seen, and I still don't feel any difference in actuation until I move to a different switch (I currently have them on an Access board with MX blacks - great partnership). They certainly feel different to type on because they are higher, and they have a different surface shape and texture. For comparison, going from MX browns back to MX blues feels different in actuation... but that's because there's a difference of 5cN in actuation force, which is a jump of more than 10% in resistance (45cN to 50cN). I still don't see how jumping less than 1g in keycap weight can feel different, somewhere between 1-2%.
The maths tells us only what it can - that there is a difference in weight/mass/resistance/acceleration etc.; but it doesn't tell us that the difference is perceptible. :)
No need to compare DCS and Cherry. Cherry Corp. themselves have made both thin and thick PBT caps.