It's all about personal preference.
I've wrapped in foil, not wrapped at all and now I use butcher paper. I usually wrap at about the half way point, or a little after. For me, that's about 6 hours on an 11-12 hour smoke for a brisket that started out in the 12-13lb range. The internal temp is usually around the 170 mark when I wrap. The brisket will cook fastest when wrapped in foil, and slowest when not wrapped at all. Not wrapped had the thickest and most pronounced bark, foil wrapped has the softest bark. Butcher paper is in between.
You really have to try it each way and find out which way you like it best.