Personally I've only injected a brisket once and I didn't like the way it turned out. Tasted like pot roast to me. Very odd.
The best brisket I ever cooked was a Snake River Farms wagyu. I did nothing to it - just kosher salt and coarse grind black pepper. It wobbled like crazy, was moist all the way through.
There is so much marbling in the wagyu that I don't think you will find it to be dry. I cook them fat side down in the FEC-100.