I’ve bought literally many hundreds of parts from RockAuto. And at all price points, too, from weird no name stuff to major name brands.

I’ve only had 2 defective parts, out of hundreds of items ordered. One ultra cheap ball joint was incorrectly manufactured.

One ultra cheap TPS didn’t work.

A couple of oil filters would not fit every car listed in their application, only some of them due to quirks in the oil filter manufacturing.

I had problems with my 2000 Volvo S70 parking brake. For whatever reason, Rockauto’s catalog listed parts for a different Volvo parking brake assembly as fitting my car.

I have never encountered a counterfeit part. Every part has been great quality…. except for the lockwashers for one ball joint. They were flimsy, so I used my own better ones.

Fwiw, I’ve had fewer problems with Rockauto than from my local auto parts store.