For every manufactured rub I have tried, there are 30 I have not tried, so take that with a grain of salt...
Brisket: I usually use canning salt, cracked black pepper, roasted garlic powder, and Temper Temper (a pepper blend from Pendery's). But of the bottled rubs I have on hand, I like Rudy's Rub and Smokin' Guns Hot. I'm currently testing some Big Poppa Cash Cow, but don't have enough cooks with it to comment.
Chicken: Plowboy's Yardbird, Birds & Bones, a market re-branded rub called Olde Canadian Chicken Seasoning (It's sort of a Montreal style seasoning, but for chicken) and two of the Dizzy Pig Rubs ... Dizzy Dust, and Tsunami Spin,