Interesting, I hardly ever use mine, and the one I have is actually my parent's old one that they gave me since they never use it either. It's pretty beat up by now, from getting shoved in the utensil drawer all these years. I think it's got some rust on it too.
I didn't even know they made these in plastic until I just started looking them up online, however I would stick with metal still. But I would go with one of the more modern designs, which are much sturdier than some of the older ones I've used which would get all bent easily. Of all of the plastic designs I've seen, the wires were too thick to remain reasonably sturdy, but they also made it harder to cut into the dough with.