I actually have purchased from them. If it's a model specific part you order with a trusted name on it, you're going to get the name brand part for the right car.
It's basically a walmart for performance parts.
walmart will have some specific things you're looking for, but you'll need to sort them out from the rest of the generic junk that's on there.
their customer service isn't bad at all, they worked with me while i was in iraq, and had things shipped from the same order to 5 different addresses (i bought several buddies some car stuff for christmas while I was deployed), gave me a military discount, and had fast response times.
granted, all this was 4 years ago, so things may have changed, but that's my experience with them.