Well, it was easier to feel the difference between the gray alcantara sp4 keyboard and the regular sp4 keyboards (I had the teal keyboard, the blue keyboard, and the alcantara gray for the sp4).
the alcantara for the new type cover is smoother than the material on the regular sp4 type covers. the backside of the new type cover is closer to the backside of the sp4 keyboard than it is to the backside of the gray alcantara sp4 keyboard. the gray alcantara sp4 keyboard backside was thicker feeling and more fuzzy-like.
but trust me, if the new alcantara wears like the previous alcantara, it will wear better than the regular sp4 keyboards. My favorite SP4 keyboard was the teal. But I only took it out for "special" occasions because it looked older faster (it wasn't exactly "wear" but somehow looked older as I used it). So I thought since the alcantara would be more durable, for 90% of my work, I would use the gray alcantara keyboard. And it does look more used than my teal keyboard by a little bit but considering I abused it for 90% of the time versus the 10% of the time for the teal keyboard, I was impressed. And before anyone jumps on any of my comments, the carbon fiber on my XPS 13 somehow stopped looking new after a very short time. Most devices don't look new after you've owned it for awhile. But that carbon fiber... Maybe it's like T-shirts that only look new when you first buy it but the first time you throw it in the wash...
I think ultimately it comes down to color preference. For me,
#1 is the burgundy new keyboard.
#2 is the SP4 teal keyboard.
#3 is the SP4 blue.
#4 is the new cobalt blue.