I like to experiment w/different rubs. S&P with a good smoke and properly cooked is tought to beat. It is like a standard cheeseburger - seared 80/20, american cheese, LTPO, mustard, griddled bun. That's the "you can only have 1 burger order the rest of your life" I can eat them every time and be happy.
That said - the last couple of racks I've cooked I've used part of Meathead's method of lightly saucing after removing from the smoker then put it under the broiler in the oven a minute or two to carmelize the sauce. I like Lilly's Carolina Sauce because it has a lot of vinegar and isn't too sweet. Avoid the sugar free version like it is herpes.
I could do the sear on the grill but it'd just be a waste of lump to get it up to temp if I use the same rack level, or I'd need to take the ribs out and remove the rack to access the lower rack. On a cookie sheet under the broiler is too damn easy.
Staff - take out the trash.