To be honest it depends on my mood which way I'm going with a rub or even a spritz.
However, in my opinion the biggest change in flavor for me is the woods I use and if I was gonna "swear" by one for pork it would be a combo of hickory(or pecan) and cherry. The hickory and pecan is either or but the cherry has to be part of the combo.
And cherry by itself with beef.
Now juiciness is all down to fat content and cooking technique. The faster(hotter) the cook the higher the finish temp and the longer the rest(for me). The slower(lower temp) the cook the more I can cut off my rest. I look for butts that are marbled as well as I can see and depending on who is eating I either trim the fat to 1/8th inch and crown to render more from the cap and spritz at the end to have a sweet crunchy bark to blend into the meat or 1/4 and don't crown to skim the whole thing off to make the pork more "lean" for the people that fear fat for some reason.(been known to keep the scraped fat to make a heck of a sammich I don't want people seeing me eat) LOL!!
Almost forgot. I always buy my butts in the cryovac twin packs. I've never liked buying butts that have been handled a lot before i get them. That's a good way to live your life in more ways than one.