I was a part of the first drop and ordered both the nylon and smooth options since I was not sure which ones I would prefer. I find both the nylon and the smooth finishes to be comfortable, however within a few hours of unpacking the wrist rests the smooth wrist rest has started 'cupping' (see picture). Although I prefer the smooth texture the cupping is a deal breaker for me. If I were to buy again I would definitely go with nylon.
mettaNylon is a weaved fabric material that can handle expansion / contraction due to temperature or any other factors. I am not sure what material is used for the smooth, but by the look of it may be a rubbery or silicone material, which may be susceptible to shrinking / expanding and then holding its shape. It would be interesting to see what the smooth pad above would do if placed into a freezer for a few hours.
isalteverythingI did exactly the same thing - I wasn't sure about the difference and since I have two keyboard kits on order (supposedly will be here Monday!!), I ordered one of each. My "smooth" rests are cupped exactly as shown in the pic by isalteverything. But the nylon rests are perfectly flat.
I tried putting them under a couple of heavy books for several days to flatten them out, but it had no lasting effect - they went right back to being curled.
I haven't used them in anger yet - all I've been able to do is to rub them longingly and imagine what it will be like once my keyboards are here and built... but my initial reaction is that I slightly prefer the feel of the nylon over the smooth.
I did put them in front of my current keyboard for a few minutes and the "cupping" wasn't really that noticeable. To me, it's more of an aesthetics problem than anything else.
The manufacturer could perhaps compensate for this by stretching the foam on the bottom slightly before gluing on the top layer - it would then tend to "snap back" to its normal position and counteract the (apparent) tendency of the top layer to curl up. But that may be much easier said than done.
Mentalmaniac76I'm well aware what nylon is; I was under the impression that the nylon material was only covering the wrist rest like a mouse pad. The whole thing isn't made of nylon. The fact that it's flexible and can contract doesn't address why the nylon version doesn't warp since it would just warp with the foam underneath.