The Smoke Shack used to have and use the Shack recipe. However, I've heard they no longer use it. I don't know, haven't been there in a while. Don't know if they are family members or former employee's either. Not sure the same owners have it either. Supposedly they used to sell the stuff by the gallon to the passing truckers and made good money doing so.
HB's BBQ, in SW Little Rock, is run by family members and still uses the original sauce. Unfortunately they have no concept of preparing?, holding?, or serving meat. I've only eaten sammies from there and they are like sawdust on buns covered in cabbage and sauce. Everywhere else I've ever eaten that used Shack sauce puts them to shame.
HB's is the last joint I'm aware of that still uses Shack Sauce exclusively. At one time it was the only sauce I knew.
I can understand folks not liking Whole Hog. It's run by old comp cookers and they teach their franchisee's much in that style. Also, they don't serve hot, temp wise, BBQ. It's closer to room temp but it's well cooked and tender. Not juicy, but not dry like HB's. It's also pulled pork when Central AR has traditionally been a chopped BBQ area. That old Shack influence from Carolina. They cook on gas fired Ole Hickory's so not the most smokey and not the most bark. Shack's butts like like big chunks of coal before chopping.
Their ribs are the best I've had in Central AR. Not overcooked, or under cooked and tough.
Another thing with Whole Hog is, AFAIK, all but the original on Cantrell Rd. is a franchise and, as such, some variation exists.