I've tried most of the commercial rubs and a few concoctions of my own -- all were good. But, I keep going back to a medium coat of good ol' Montreal Steak by McCormick. It is relatively inexpensive compared to most and I like the garlic and onion touch it adds. The saltiness disappears during the cook. For a finish, I put some in the coffee grinder and powder it, then sprinkle very lightly on the finished product -- slices or burnt ends.
What does the most for brisket, in my opinion, is the injection. I use Butcher's for Beef mixed 1/2 strength. Moist brisket is much more pleasurable than dry. Also, if you sauce it, just use some of the juice from the foil or pan stage instead of anything sweet.
Finally, I always use mesquite pellets. Some find it too strong, but I think it compliments the beefiness factor. In a PBC you could add some mesquite chips early in the cook.
Hub