While I do agree that steel spur gears tend to "cover up" other problems and if all is well a plastic spur should hold up to even the strongest engines in the heaviest trucks, there are times when a steel spur is the better choice, and maybe devoejl is nearing that point. What I mean is, after checking and rechecking the mesh and threadlock and alignment and everything else, the owner will be very frustrated. They can keep searching and testing and destroying plastic spurs on a daily basis while trying to figure out the problem, or they could switch to a steel spur.
The steel spur doesn't fix the actual problem, but most likely it will cover it up sufficiently such that the owner can stop fighting the truck and start driving and enjoying the truck.
I burned through two plastic spurs during the first three years of owning my Savage, but then I started blowing them left and right, couldn't even get one tank through before the spur was destroyed! After about the fifth plastic spur was gone, I though to myself, "I could keep chasing this problem down, put a new plastic spur in every five minutes, and get frustrated and probably stop driving my truck for a while, or I could bolt in a steel spur and stop thinking about it and just have fun." So I did. I don't regret it.
Sure, whatever the problem was that caused the failure of the plastic spurs probably still exists, but the steel spur can handle whatever the problem is, and I'm enjoying my Savage again.
To answer the question from earlier, there really isn't much of a downside to a steel spur gear other than you must run a hardened clutch bell (no big deal) and there's a little bit more rotating mass your engine has to move. All else being equal, your truck will accelerate marginally slower, but I doubt you'd even notice a change.