I've been to two DDD restaurants, both in Texas. In Dallas I went to the Twisted Root Burger Company. They specialize in interesting burgers and make their own root beer. I had the burger with tangy buffalo sauce and blue cheese and sweet potato fries. Also the house root beer. The burger was very good, not the best I've had but this is not a fancy restaurant by any means. The fries were great and the root beer IMO average. I prefer IBC or Hires. It's a fun place to visit and the food is interesting and good. I'd go again and try another of their interesting burgers, perhaps buffalo.
In San Antonio (actually Adkins) I went to Texas Pride BBQ. It was just as advertised, meaning a typical BBQ joint atmosphere, this time in a converted old gas station surrounded by old vehicles. I think I had the brisket and sausage combination which was excellent. Terrific place to eat.