This is a common myth. I've concluded Trader Joe's exists to give a veneer of guilt-free-ness to buying junk food. Avoid the cheese and meat at all costs.
Trader Joe's is great for prepared meals, but they are absolutely the worst grocer with regard to meat and produce. Often substantially worse than discount grocers like Krogers or Smart and Final.
Mostly quality, but also pricing. IMO the meat is average price and the produce is maybe a little cheaper, but the quality of both is generally very poor, especially the meat. I've had meat that was a few days away from going rancid from several different Trader Joe's locations.