You pay for what you get, really. That's how it has gone for me, at least. I bought a HP dvd1270 and it works perfectly well for me. Very fast, burns discs properly, etc. Usually Toshiba drives have failed on me, but I've always had great luck with Lite-On and HP. Oh, and another warning from personal experience... if you go used, do not get a Matshita/Panasonic. They have all failed on me so far.
As for the quality aspect, I am fairly sure most of them will have a plastic face plate. I don't see any other substitute. The metals aren't the strongest, but if you don't drop the drive or put a ton of pressure on the thing, it should be fine. My main concern would be about the optical lens and the gears. That varies model from model, so just do some research before you buy to see what people have to say about the quality.