My only knock on the store bought stuff is the amount of preservatives they have. In my opinion, the Bryant's store bought rub is a pale comparison to the real restaurant (it seems a bit too salty); I can't speak for the Gates rub. That being said, it could be my palate because I think Head Country and Bad Byron's Butt Rub to be too salty as well.
If you don't mind a little DIY, this is a recipe I've had for a while that is alleged to be the Bryant recipe if you'd like to give it a try:
ARTHUR BRYANT'S RUB
1 cup salt
2/3 cup paprika
2/3 cup sugar
2/3 cup packed brown sugar
1 tablespoon ground mustard
2 teaspoons white or black pepper
3/4 teaspoon ground celery seed
2 teaspoons powdered onion
2 teaspoons powdered garlic