I did a couple of chuck roasts brisket style on the BGE yesterday. They were so tender that we could cut them with a butter knife. Better than any brisket I have ever done. I really recommend you try this, especially if you don't need a huge piece of brisket and are cooking for just a couple of people. I usually do two of them and use one of them for chili later.
My method is as follows:
1. Inject a 3 lb chuck roast with Rick's Sinful Marinade (Worchestershire Sauce, beer, water, vinegar, cayenne, celery seed, some rub, BBQ sauce, Accent, and beef boullion base)
2. Drain off any remaining marinade and rub down with generous amount of yellow mustard.
3. Apply generous coating of Montreal Steak Seasoning (or rub of your choice)
4. Smoke at 225-250 until you hit 170 internal
5. Wrap in pink butcher paper and put back on the smoker until internal temp 200-205.
6. Rest for a couple hours in cooler if you can (I wrap in towels and put in cooler or insulated zip bags).
Comes out amazing.