What do you want to do with it? For pulled beef brisket (i.e., shredded), over 205 is needed (maybe 210). To slice it, anywhere from 195-205. My mentor tells me the way to tell if it is done is to push your finger into the fat cap. When you go right through (like jelly), the brisket is done. He does it in a double foil pan. I have done it in the pan and on the rack and can't honestly tell the difference. The more well done it is, the thicker you need to slice it to keep it together. At 195, you can slice it fairly thin. It is tender but not falling apart. At 205, if you lift one end of the slice, it might just split unless it is sliced more thickly. Check out the posts from guys like Tom and Smokin Okie. They are experienced and have great info and ideas, but in the end, it really comes down to what you like.