FWIW, after seeing the color rings IRL, I think both materials have color matches that are about equally good, all things considered. The PBT set has the best color matching for all the colors except for the yellow/orange. ABS has the better yellow/orange but slightly worse matches in the other colors. Since the yellow/orange is rather more important than any of the other colors, I'd say it's basically a wash—or that ABS comes out slightly ahead, since it also means crisper legends.
To describe the issue with the PBT orange/yellow more precisely, the best and only suitable color for that role within the PBT palette is a very light/pastel orange, almost like an orange sorbet or Creamsicle.
It is more orange and pastel than the traditional LCARS yellow (which
should actually be
somewhat orange), and it just doesn't look like anything we ever really see as part of an LCARS interface.
But as I say, in similar ways, the other colors for PBT are better matches for their own respective positions.
Anyway, hopefully my mock-ups and the pictures in them will give you some sense of the difference, but it's a little hard to convey virtually.
Maybe it would be a good strategy simply to make your choice based on which material you prefer for its inherent properties (legend crispness, feel, sound, etc.). Because I think either one of these color sets is going to make for an amazing LCARS-themed production.
Looking forward to hearing other people's thoughts. Hopefully we'll be able to start voting on these soon.
[updated to add clarifications, and added a pic for illustration]
