I would love to buy all my meat directly from local farmers and butcher the animals myself, but I don't have that kind of money, so I buy from many different sources. I try to get locally produced meat anytime I'm making a dish where the taste of the meat really shines through, and I'll use mass produced meats for dishes with heavier spicing and added flavors.
About half of the meat that I buy is mass-produced. I gave up on Jewel/Dominick etc. long ago and mostly buy from Costco, Restaurant Depot, and Peoria Packing. The difference in quality is significant to me. Some things to look out for in supermarket mass produced meat is things like pork in a saline solution. Most pork I see at supermarkets is packed with a salt solution that makes it too salty for my tastes, and can also give the meat a mushy texture. Costco and Restaurant Depot also sell meats like this at times, so always check the packaging. Supermarkets also tend to do a poor job of cutting their meat, they're more concerned about hitting a packaging size than making a decent cut of meat and it shows. Buying large primal cuts and dividing them yourself will get you much better results.
The other half of my meat purchases are a mix of local butchers, farmers' markets, and whole animals from farms. I'm a big fan of Butcher and Larder, Paulina Market, Slagel Farms, Mint Creek Farms, and a few others.
The benefits of a real butchers shop are:
- You can tell them what you're making and let them select the meat for you. You can learn a lot from talking to them about what they're doing and why.
- Their business survives by selling quality meat. They put much more attention into selecting quality animals than a buyer who is purchasing animals by the thousands for a chain (even if the butcher isn't buying farm raised animals). Many also don't have the pressure of having to keep EVERYTHING in stock. If they can't get quality sheep that day, then no lamb. I think a good butcher would rather run out of an item than buy poor quality meat.
- The selection is infinitely larger than that at a supermarket, and you can learn about different cuts.
The benefit of buying farm raised meats is primarily the quality and freshness. Pork tastes "porkier", beef tastes "beefier", etc. I prefer to buy farmed meat that hasn't been frozen, I think it has an impact on the texture. Pork is the meat that I think shows the most pronounced difference between factory and farm raised. Factory hogs have been bred to be so lean that they've lost their taste, I also think that pork reflects the taste of the animal's feed more than any other animal. I always try to buy a whole foraging hog in late fall/early summer after they've been eating acorns for a month or two - you can taste it. The River Cottage Meat Book is a good place to start to learn more about cuts of meat.
You should try to do some head to head comparisons to understand the differences, buy some pork chops from a local producer and then from Jewel/Dominicks. Prepare them together in exactly the same way, with a simple preparation (i.e. grill with S+P, an herb or two, and EVOO). Eat them at the same time. It will be an eye opening experience.
Seebee describes the grading system well - it is basically fat marbling and physiological age of the animal. I think it is a useful thing to look at if you're buying something like a rib eye steak, but is less useful for a large number of cuts (assuming it is at least choice or prime). For some dishes I prefer older animals, and actually try to buy only mutton instead of lamb.