Mustard is South Carolina, Midlands to Low Country. Vinegar is North Carolina, Eastern and Coastal Plain. Upstate South Carolina and the Piedmont of North Carolina have their own style, basically vinegar and tomato, with the best-known examples being from the vicinity of Lexington, NC. Get into the Blue Ridge and you start running into sweeter style barbecue influenced by Tennessee’s favored style.
Then, you get into the traditional sides. Coleslaw with Eastern NC is sweet and creamy, a nice counterpoint to the pepper vinegar tang. Brunswick stew in cooler weather. Western NC has hot, tangy barbecue slaw, a nice counterpoint to the comparatively more sweet vinegar and tomato barbecue itself.
I’m getting hungry now.