I buy from them all. I feel that I lean toward Advanced Auto Parts if I need something right away or whomever has it in stock. Rock Auto most of the time. NAPA I feel has some things I can't find elsewhere. They all have some little things that are different from others, just depends on what I need. Hard to pay some of the prices of the local guys when Rock Auto is sometime 20-30% cheaper for the same exact item. Ebay for some things too, just depends on who has the best price on the same item and how fast I need it.
Wally world for oil and batteries.
I'm lucky, they're all within 30 or so minutes of me, including the Jegs warehouse. Been known to drive to Summit a few times too to avoid freight on AMD metal, they stock some of it.
Know a guy that retired from NAPA. NAPA used to carry, in my opinion, higher quality parts but, for most things, like he said before he retired, it's pretty much the same as all the other guys now.