I've used Rockauto alot. I have real knowledgable/helpful people at local NAPA and some "old" guys at Kragen, but you can't beat that Closeout parts list I get e mailed to me about 4 times a year and I'm on an extremely tight budget. I stock up on seals and stuff I know I'll eventually need.
I've only gotten 1 Bad part. (an "improved" Jeep 4.0 exh. manifold). I couldn't get ahold of them to return it,,but that's my problem with the computer.
The shipping can get you if your unaware that stuff comes from different dealers. The shipping rates are very fair, though and you'll still comeout ahead with savings.
( unlike Parts.com that rips you off charging ever nickle and dime on special packing charges they don't bother to do. It makes the price inflate equal to ordering from Korum, etc. , and there you get Servive. Sorry for rant, they really screwed me.)

dave h.
'89 Raider V6 5spd;Aisin Hubs;; Gen2 LS: frt. brakes, rear coils;U.C.arms;R.trailing arms;idler arm; rear LSD axle w.disc brakes ;2 battery system for Dog's fan; relocated ECU; custom bumpers;J.Baker receiver;Conferr roofrack; t-bar crank.