Interesting topic as I was just thinking about this yesterday when I was in one of the grocery stores.
I realized that I don't buy much of anything at the grocery store anymore. My main reason for buying local is because I can know how the animal is being fed and the "husbandry methods" being used. I won't purchase beef from farms that feed gmo in any form. Grass fed only for the rumenents. If I purchase chicken or eggs, I look for REAL free-range where they get plenty of meat proteins from bugs, snakes, mice...anything they can catch! (And certainly not "vegetarian chickens" 
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I know a family that raises a low line Angus/Hereford cross on all grass. Whenever they are ready for butcher, they call several families that purchase from them. They offer sides and quarters at the same rate you'd pay for grain fed which is a fantastic price. Using the low lines, the sides and quarters are small enough that they don't break the bank so I can afford it.
Sometimes they do the whole animal in ground beef rather than cuts which I like because we use a lot of ground. When done that way, they sell it by the lb. Their price for the grass-fed is less than half of what it would cost at the regular store from a place that uses GREAT husbandry practices. I just brought home 250 lbs. of ground yesterday. Several other people will get part of that leaving us with about 150 lbs. for the freezer over winter.
I live in Northern Indiana. There is a wonderful farmer's market in South Bend that I remember going to with my mom and grandma when I was shorter than a gumball machine! It is still there with a wonderful array of fresh fruits and veggies, meat, cheeses from somewhat local creameries, crafts, jewelery, potted plants, plant starts, freshly butchered meats, some grass-fed/organic..you name it. Everything from very conventional (read: full of pesticides and gmo) to those raising by "organic principles" (meaning they can't afford to be certified but are actually more conscientious and often more honest about how they grow) to certified organic depending on who you purchase from.
There are also other farmer's markets in the area that offer only organic growers.
So...for me, knowing the source, the animal husbandry methods, etc. is the selling point. I no longer purchase meat, milk or eggs from the grocery. I only purchase veggies or fruits from the grocery if they aren't in season in the area then then I usually try to choose a small, family run store to support the folks in the area.
And...Hi to everyone! Been a long time since I commented 