The truthful answer is that it depends on the company that you are looking at to possibly give you an aftermarket part. The quality of aftermarket parts can vary wildly from a company from to another company and you have to make sure that you do your research before you fully engage in getting that part. You may make a mistake that you regret otherwise.You could potentially damage your vehicle when all you wanted to do is fix it.
For example, the writer of this article bought a non-OEM charger for their Apple laptop. The charger actually came apart and now will not charge properly without sparking when reattaching the piece so that the laptop can charge. Not only is it a risk to the computer but it is a risk to the person as well. The same could be true of your vehicle. If you use a non-OEM part without specifically researching the company that is providing the part then you could have a similar problem but much worse depending on where the part is located or what it is supposed to do. We all know, in the back of our minds, that we should be using OEM parts. But, the fact remains that aftermarket parts can be cheaper at times, however, they can cause more problems than they are worth as evidenced by the laptop charger.