I wrap my brisket in butcher paper around the 160-165 mark, then back into the smoker to push through the stall and on to 195-200.
I find the butcher paper retains the bark crunch better than foil but still allow some smoke to continue to penetrate the meat but not as intense as if you chose not to do anything. Your wood choice and smoke certainly plays a part in that too.
I have used foil in the past and it certainly helps retain moisture and braise the brisket, but a couple of times when I used foil, it probably was in the foil too long and the brisket became more like a pot roast, wasn't over done, its just that the steaming effect really broke down the meat fibers, however, it still tasted good.
The great thing about brisket is trying different ways of cooking them and figuring out which way you like to cook it. Bottom line, as long as you treat it like a marathon cook and not a sprint with low heat, good smoke, it's pretty hard to mess up.
I have gone from no wrap to foil to butcher paper. You might prefer another way.
Hope this helped... good luck and enjoy cooking that brisket.
btw I use the peach butcher paper... sort of an Aaron Franklin thing/Texas style brisket.
Tom...