What difference did you find by not injecting?
I'm curious about your opinion too??
I don't think a brisket, properly cooked, NEEDS any injection.
I do think that it widens the window of success in moisture and maybe flavor, but when a brisket "gives up" and breaks down properly, it has a wonderful flavor and is really juicy. If you overdo it a bit, I think the injection may assist in keeping it from drying out as bad, but maybe not even.
The SPOG brisket got a bit overdone. When I wrapped and put it back on the BGE, I added more charcoal and opened the vents up and forgot about them. 1/2 hr later and it was cruising at 425. When I checked it at 5:00, it was probe tender but the IT was about 212.
It wasn't quite as juicy as the KC's rubbed brisket. IF I'd injected, the injection MAY have kept it a little moister, but I'm not sure.
In the end, the au jus really saved it. I poured equal amounts (about 2.5 C each) au jus over each briske after slicing and the SPOG brisket soaked it up like a sponge. I think that properly used, au jus will/can help with moisture and flavor as much as injecting.
Still.....if it had my injectors working, I'd have injected them.
I do a simple injection at home. I just make up a beef broth with bullion, add SPOG to it to taste and inject that.