Jack Stack is good, but Kloset is right about the wait. Gates is also pretty good. I haven't made it Oklahoma Joes, yet, but I've heard nothing but good about it. You ought to make it by there, as I hear they are building a big restaurant to move into. Usually, bad things happen when a good place moves into a newer, bigger building.
I haven't had Kloset's experience with Arthur Bryant's. It's always been pretty good to me, but the sauce is somewhat on the weird side. Be sparing with it, until you find out you like it. The "hot" sauce isn't worth a flip.
True "burnt ends" are the edges (thinner) parts of the brisket that get very, very cooked. They aren't so much burnt (i.e., they aren't just a bunch of charcoal), but they are tough and like jerky. Basically, they are little hunks of bark. You don't get enough true burnt ends off any brisket to make any more than one decent serving, unless you leave the thing on the pit for a couple days. So, since they are so popular, folks simulate them by chopping up some brisket and putting those pieces back on the pit for a while. "True" burnt ends come from anywhere on the brisket. However, because a sliced piece of flat usually brings a better price than a chopped point, restaurants usually chunk up the point and cook it to "burnt ends." A little more time on a fire that's already going, and they get to put a premium on the product.
TL