Uncle Sam's is and institution and I won't hear a word said against it, especially a Biggesf Burger with blue cheese sauce. By the same token, Grubbs is similarly iconic, and brilliant.
All that said; Burger Bros blow both out of the water in terms of quality.
Glad to see the Troll love is still alive and well, and just like HT I'm glad to see that he's still about, and still foraging/cooking, even if only for himself. His Smokey Mountain was the best burger there has ever been, or ever will be.
Now he's gone, the true answer to this question is...