I am surprised, I have never had even one issue and been using them for at least 10 years. In fact, I buy almost all of my parts from them these days. I have also had numerous returns too. I have had them OK some returns beyond their policy too.
Shipping I know when I buy the parts, and I know if I have to return something usually the shipping will be on me. I cannot see other online retailers being any better to deal with and for what I save, usually I can afford to wait. I find it more difficult all the time to pay a third or higher for cheaper brand parts at the local stores when I can get better for the same money or cheaper at RA.
I know many guys are big NAPA fans, I never have been one of them, my first experiences with NAPA their service sucked. After that their prices were crazy high compared to everyone else so I never really cared for them.