I have been using rockauto since 2009 and have given them plenty of business on several projects.
Even with shipping their prices meet or beat the local parts stores (in canada) and when things go on closeout, which they often do especially for our defunct models, the prices are unbelieveable. $30 for a complete clutch kit. $15 for a piston ring set. Beck/arnley parts, old boxes sure, but so are our cars!
I feel bad for the reputable members having trouble, but I have not had one problem, know what you're ordering, do your research, price compare and 95% of the time rockauto wins.
About to give them a couple hundred bucks on closeout parts for a 3G prelude i'm working on. Over $500 in parts locally for less than half the price!