As you might see, the aftermarket one might be sturdier and if you are going to be hooking and unhooking it up, this might be an issue. then again, if you're simply going to hook it up once and leave it, it may not be an issue.
As far as to picture quality, there may or may not be a difference. Seriously. You might want to try it and see. If there's no differene and you don't feel you need the aftermarket jobbies, take 'em back and but a few DVD's with the money. The Incredibles is coming out pretty soon...