True- Rock doesn't seem to be much different than any other supplier in that regard. Being a reseller, they handle a lot of the brands that everybody else sells- they buy up overstock and closeout inventories from various warehouses and chain stores and sell them at discount prices, albeit with outrageous shipping prices- so you can kind of pick and choose which parts you're going to get. Heck, I've even gotten genuine "Mopar" parts from them. Returns are a pain, though. You do your due diligence and hope for the best, like most places.
I've only had mixed luck with well-known name parts lately, as a lot of them have been going overseas and QC isn't what it once was... have you checked out Wix filters lately? Even some Timken/National stuff is Indonesian (although I haven't had major issues with it yet).