We've had our KA for 30 ish years. A just 3 or 4 years younger friend has her mother's KA.
I will say though that the older KAs have all metal gears save 1 hard plastic gear that is there to fail if you overload your machine so you don't burn out the motor. I know this for a fact as I did exactly that with dough for 12, 12 inch or so pizzas. My hubs, CraigC, is one of those people that can take something apart, fix/replace what is wrong, put it back together and it actually works so we know for a fact what is in the inside of our KA. Anyway, point of writing that is that supposedly the newer machines have more of the hard plastic gears, if not all. I don't know if that is true or not.
We have quite a few attachments, all but 1 made by KA. I did buy a pasta roller/cutter in the last year or so from the after market and it works great, and was about half the cost of the KA one.