I used to brine butts, but it really was a royal pain in the arse. Once I did a brined one and an injected one at the same time and I honestly like the injected on better. I haven't brined one since. Now birds are a different story though. I usually brine pork chops and sometimes tenderloins too though.
My butt injection is pretty simple though. It is just AJ, AC vinegar and salt.