Drop + Zambumon MT3 Serika R2 Keycap Set

It's mainly my personal preference: sound and touch/feel. I've heard about ABS discolouring which would make ABS actually worse in absolute terms, but I didn't observe it on any keycaps I do possess (MT3/GMK/SP-SA), seems to be thing of the past (?). PBT definitely has higher pitch than ABS. BTW: I'm handling lack of R5 on MT3/ABS kits by putting 5th row key upside down - works nice for me.