Depends upon what you are looking for.
If you bag and tag, most will pull at 190 and allow it to rest where it will normally continue the temperature rise to in excess of 200 degrees.
If you are doing old school low and slow I usually wait until I am ready to pull it, but I really like that 203 IT. Remember no matter which way if the meat is still rising and you think it finished it will continue to raise in temp some.
Make sure and allow the meat to set and cool. Two hours is not too long. If you try cutting it hot even properly cut across the gain with a surgically sharp knife, it will fall all over the place. Seriously I never heard of pulled brisket until I can here. But Myron, calls it pulled to. Kinda like blackened fish I guess..LOL
Cool, allow to redistribute, cool allows meat to cut, beside who wants to burn their mouth? Let that nice rendered fat recongeal a little.