Meat quality is one of many factors that will affect the end result of a barbecue.
Whether competing in a World Championship BBQ Cook-off, or cooking for family and friends in the backyard, the meat you start with will greatly affect your final results. You wouldn't take a Volkswagen Beetle to race in the Indy 500, so you certainly don't want to take a cheap piece of meat to a bbq cook-off. Or, to put it more bluntly, "you don't take a knife to a gunfight."
Whether it's chicken thighs, drumsticks or breasts; whether it's pork shoulder, picnic or butts; whether it's a brisket packer or brisket flat; whether it's a loin back, baby back, spare, or St. Louis-style pork rib....your barbecue needs all the help you can give it.
Or, to put it still yet another way..."garbage in, garbage out."
Some general guidelines for meat selection:
For overall tenderness and cooking consistency, it's more desireable to use a dark cut, like thighs or drumsticks versus a white cut, like breast. Avoid the brands that have "up to a 15% sodium solution added". You want "natural" chicken, often called "Amish" by butchers.
Resist the temptation to purchase the $.99 / lb. economy brisket flat that's on sale and instead, ask your butcher to order you a Certified Angus Beef (CAB for short) whole brisket ranging from 11 - 13 lbs. Don't be shocked if it's $3 / lb. or more. For brisket, marbling is key. CAB offers the marbling you need and whatever you do, do not let the butcher trim the brisket for you. You need to trim it yourself.
The most forgiving cut of the four competition categories I've been discussing, but your results will be better with a "shoulder" or a "butt" versus a "picnic".
If you prefer spares, ask the butcher to order you some "3 lb.-and-down" spare ribs and definitely ask them to get you some that haven't been soaking in a "sodium solution". You'll need to learn to trim them St. Louis-style. Anything bigger than 4 lb. per rack and you'll end up with rib bones I refer to as "brontasaurus" bones (big bones from a big hog) that are not very appetizing. Baby backs or loin backs will work well too. It really just comes down to the preference of the cook, but again take special note to avoid the "sodium solution."
Find yourself a local "mom and pop" butcher shop and explain to them what your end goal is and that you are a bbq nut, and they'll probably bend over backwards to help you find just what you're looking for. If they don't. Find another butcher.
If your competing, stop by with pictures of your turn-ins or bring in a trophy or two when you win one and you'll make your butcher happy. Like most everyone, they will be happy to know they helped you succeed.
If you're butcher does right by you, do right by them and tell your friends about them. That way, everyone wins.