The Professional KitchenAid mixers (i.e. the ones with bowl-holding arms) are all metal gears, with an electric controller to protect the motor from overtorque. The tilt-head models are mostly metal gears, but have a single kevlar gear that's designed to break to protect the motor from overtorque.

Stripping the plastic gear in the mechanics is like blowing a fuse in the electronics. It's possible it was a bad component, but it probably means you've overloaded the circuit. If you need more torque, buy the models with the bigger motors designed to handle it. The main trade-off between the various mixer models is basically price vs max torque.

I agree. Seems a lot of new kitchen devices seems to fail by either some plastic gears stripping or coming loose from the shaft. My mom has 50 or more year old stuff that still works but the newer devices all break. Even very expensive ones.

To be fair the article is talking about new kinds of plastics that might actually be superior to metal gears in the future. The consumer grader plastic gearing of today who's primary advantage (AFAIK) is cost do kind of suck.

When I was a child I can remember my mother deciding the same thing when sewing machines began switching to plastic gears.

It's a little disturbing how cheaply constructed the new Kitchenaids are, especially for their price tag. The ancient one that is a family heirloom weighs about 15-20 pounds more than newer models, and the base is cast steel. The moving parts have proper ball-bearings in them. I think you could set a bomb off next to it, plug it in and whip up a batch of pancake batter.