As far as the food I eat, I always try to get the best quality I can find, which is not very good but I believe is at least above average. I do have a Brix refractometer. I had mistakenly bought a Sg/Salt ppt refractometer at first but they let me exchange it for a Brix refractometer, so I've been testing all my produce.
Having read about "High Brix" produce, and seeing what Brix % they are capable of producing when grown in the right conditions. I must conclude that even the "decent" commercial produce you might find is still crappy compared to "real high Brix plants."