Tri-tip is a California cut and a Texas argument. The cut comes from the bottom sirloin, was popularized by butchers in Santa Maria after World War II, and is the rare American steak that is somehow both regional and contested between regions. Texas pitmasters argue it's a roast. Californians argue it's a steak. Everyone else mostly ignores it.
David Sandusky runs BEAST Craft BBQ in St. Louis, plus Smoke & Kettle in O'Fallon, Illinois. BEAST has been on every Midwestern "best BBQ" list since it opened. He grilled tri-tip on television against a man who has been grilling on television for twenty-five years, and won.
St. Louis BBQ is not Memphis BBQ is not Texas BBQ is not Carolina BBQ. Bobby has cooked all of them. He has not cooked any of them as long as Sandusky has cooked his.