Extend the question to ABS or PBT in MTNU?
Well, there is no ABS in MTNU. Every time I've seen someone ask about it, there'll be one or two people who've actually brought or are bringing a MTNU set to market say something like, "might be interesting to try, someday" and everyone else in the "room" (ranging from designers to sellers to people who've touched it once to people who've bought every MTNU set) act like they're watching the chestbuster scene from
Alien for the first time, at the mere thought of ABS MTNU.
That said, I think Piperaceae's point up top about MTNU being exactly the right level of smooth but still somehow just a little bit grippy is spot on. It seems smoother to me than even every brand new set of GMK CYL I've ever touched, but I also never feel like my fingers would slip off of the key if it were... IDK if the key were a sidewalk and it were raining.