I use a pellet smoker. I recognize it's not traditional, there are better options, etc. However, its within reach for most people and it doesnt take up a huge amount of space in the backyard. I have cooked dozens of briskets, and this is the method I find to be the best for a few reasons:
1) Developing bark on a pellet smoker can be tough, but this way works well
2) I like to sleep
3) Its pretty surefire for how expensive briskts are nowadays

How it started

I started on the (large) Big Green Egg. It wasnt large enough. I chopped my brisket nearly in half, and the edges draped over the heat deflector. It had great bark! But it was salty, overcooked in nearly every way, but still edible.

My first brisket was nearly my last. I moved to smoking chickens, pork butts, and fish. 

As a joke, on fathers day, Ayla got me a masterclass subscription, in which Aaron Franklin has a class. I watched it that day, loved it, and was determined to get better. Ayla had also been looking for smokers on Facebook Marketplace, and found the perfect one (at an incredible price) the next day. David and I showed up shortly after to pick it up, cleaned it, and that night was the first time I cooked on it. I think it was fish, but I honestly cant remember. 

I cooked us a brisket shortly after, and while they said it was great, I knew I could do better. I changed my seasonings, I changed my methods, I changed my cook times and temps. I isolated as many variables as I could with my trusty thermometers, and finally landed on this. 

Trimming

Do this 2 days before you want to eat. So if this is a brisket for Saturday, complete this on Thursday afternoon/night. It does take some time to get this right, and I can try to explain how to do this. But honestly, just look up youtube videos of Aaron Franklin doing it. He slows down nicely and explains exactly what he is doing. You should be able to follow along relatively easily. 

DO NOT THROW AWAY THE FAT

There is a soft fat - it's white, pillowy, and will kind of melt between your fingers. This is what you want to keep. Everything else - the yellow fat, silverskin, and attached bits of meat (don't go crazy, just remove the big clumps) - can be discarded. Put this in the fridge until its time to cook. 

After you trim, you will need to season your brisket. Lather it up with some yellow mustard (you will not taste this once its done). You will probably use a couple tablespoons. Essentially, you are getting the brisket surface wet so that the seasoning will stick to it. 

Sprinkle seasoning from about a foot above. I like to use one of the 20oz spice containers, but it doesn't really matter.

My current seasoning mix "Brisket Rub V1" is:
1 cup ground pepper - 18 mesh
1/4 cup mortons kosher salt
1/4 cup Lowry's seasoned salt
1 Tbs Garlic powder

"That's a lot of pepper!" Yes it is. Smoke sticks to the pepper, so thats why it's there. 

You want to season the brisket evenly, so you will get some of it on your counter. You should still see the meat below the seasoning, and you dont want clumps in certain areas. This part is some of the trial and error based on your taste... Watch Aaron do it. 

Once done, place on a sheet tray with a wire rack in your refrigerator, with the part you pulled the fat from facing up. 

Cooking

The day before you are scheduled to eat, so in this case Friday, pull your brisket out of the fridge an hour or two before you plan to put it on the smoker. This allows it to slowly come up to temp. Yes, the inside will still be very cold, but you wont shock the cold meet putting it into the smoker. Place your trusty probe thermometer it the thickest part of the brisket. (Pro tip - if wireless, make sure the transmission interval is set to every couple of degrees, or else it will die before the morning)

Set the smoker to around 200 degrees. Once up to temp, place your brisket on it, closer to where the stack is. 

Remember all that beautiful fat you saved? Place it into an aluminum cooking pan and put it anywhere on your smoker. 

2:30 - 3:30 PM - Check the Brisket 

Once the alarm hits, you start checking every 15 minutes. Take an instant read thermometer and poke a 2 or 3 holes in the top of the brisket - left, middle, and right. Place the probe straight up, and wiggle it around.
If the meat feels firm, it needs more time
If the meat feels somewhat like stirring peanut butter, pull
If it feels like stirring a chili, its over cooked

If the flat and point feel perfect, but the middle area feels like it can use a few more minutes, it is safe to pull. There will be a bit of carry over cooking that will bring it up perfectly. 

As you continue to check, use the same holes in the paper, but go in at different angles. It's important to not poke through the bottom paper. 

Keep your oven open for a few minutes, and set the temperate to keep warm. If you know how or are so inclined, you can also calibrate your oven below set temperatures, making it a few degrees cooler, which is optimal. My oven, for example, is set at 15 degrees below the display temp. So, the minimum temperature on my oven is keep warm, at 175 degrees. However, true reading is 160 degrees. 

Hold here until you are ready to slice. 

Resources I like

Aaron Franklin PBS Special

Meat Church Pellet Brisket

Mad Scientist Pellet Brisket