I’ve had pretty good luck with aftermarket remanufactured parts. There’s been a few hiccups now and then but they’re not common.
Dealers seldom use aftermarket parts (or at least the ones I’ve worked for) and when they do it’s only in certain situations, etc. (seal or gaskets, etc.)
The car manufacturers frown on a dealer using aftermarket parts of unknown origin because if an AM alternator is installed and it leaves the car owner stranded out in the boondocks at midnight the car owner will not only be blaming the dealer but also (in this case) Ford Motor Co.