Plastic - fantasic?

The 40-150 is lightweight, of cheap build, and produces stellar images.  I have no problem with this; I didn't pay very much for mine and its IQ is excellent.  In a kit lens, I'll certainly take cheap build if it is matched with excellent image quality; this provides the advantage that if the lens fails then it's not an arm and a leg to replace.

Photo below taken with Oly M. Zuiko 40-150mm on a GH2.  Can't fault the lens performance here at all!

-J