I've cooked a lot of briskets, and this was one of the most disappointing. The marbling was fine, but the deckle fat was so thick that even a 15-hour cook couldn't render it down. I trimmed pretty aggressively to start, knowing that I could always make burger grind and tallow from the trimmings. It wasn't for lack of trying! I know it's hard to predict how thick the fat veins between the muscles will be, but for the price premium of a Creekstone Prime brisket, I expected better. I'll probably stick to Costco Prime from now on.
I also cooked one of the pork shoulders alongside the brisket and that was great!