I brine pretty much all poultry and pork. However, when it comes to smoking a pork butt, I don't. I have tried plain dry rubs, mustard slathered all over with a dry rub, and just pepper/salt. They are all pretty good, but I (for ease) usually just go with a dry rub (I prefer heavy on the heat and sweet). But, I've only done about 50 or so pork butts, and there are several members here with way more experience. I also use the BGE, so my butt stays very moist and the smoke really penetrates the meat (I use apple or cherry, maybe some hickory and/or maple). I have never used the MES, so I would defer to someone with experience on those.
I also had the pleasure of meeting and learning from Elizabeth Karmel. Her recipe for a vinegar sauce to mix with the meat after pulled is pretty good. Let me know if you're interested and can't find it; happy to share (it's pretty simple).