I don't know about the Feather Popular in particular, but a razor that's partly plastic can be very durable. My Schick Krona is from the 60s or 70s, and it's lasted just fine. Same with a number of injector razors. Yes, there are cheap, flimsy plastic razors too, but don't be prejudiced against something just because it has plastic parts.
Still, I do believe in redundancy. Back when I was shaving with an Atra, I had an extra Atra handle. A backup razor is a good idea, whether or not it's the same type. And some of us have a lot more than just one backup.
"He broke and ran, not from cowardice, but from private inclination." - R.A. Lafferty - "One at a Time".