hours "low and slow". I had a 15 pounder take about 22-23 hours at 225 degrees. Final internal temp was right at 200 or so. When the temp probe goes in easy, you are there.
I use the Franklin method with pink butcher paper once the bark gets nice color. 50:50 pepper and kosher salt for a rub with just a bit of Montreal steak seasoning.
Since they take so long, I am going to do my next one at 275-300. Lots of literature out there that says you still get the same results.
Once done, wrap it with towels and put it in a cooler. You can store it for 4-6 hours and it gives you some flexibility in the cook. No need to have everyone standing around waiting on your brisket to get done. Get the best quality brisket you can. Some Costco's carry prime.