[juusto]

That's one of the reasons I mentioned those three.

I think we have to distinguish between plastic, the one that feels cheap and might crack even when exposed to cold like many of the cheap DSLR lenses. And the "new" kind of plastic that is sturdier and more resistant to drops or scratches. The FE 24-105 is the latter and it does not feel anyhow less quality than more expensive top zooms.

Plastic has its positives as well: it won't scratch as easy as metal and, specially for zooms, its lighter. Imagine a zoom made of metal like a Voigt lens.