I'm not sure that is still the case. I have an OP-Z and lurking forums for that device reveals tons of posts about build / hardware issues. Luckily my secondhand unit only has SOME broken components but it's pretty widely known as an incredibly fragile device with many design flaws
There's plenty of products made with plastic that holds up well, even in the most harsh environments.
They decided to make the OP-Z out of plastic and it didn't hold up well. It's the fault of their poor design, or at least the type of plastic they decided to use, not the materials.
