The truth is you can use either, if done correctly.
But I will tell you a short story and let you decide. At a Boy Scout blacl powder demo I was in charge of, one of the other Dads brought up a .45 cap lock that was filled with bore butter, and I mean inside the flash channel and all! The stuff was coming out of the nipple! About ten minutes later, I had the thing actually shooting! Took several gallons of water, lots of patches, and lots of elbow grease. Moral to the story is too much of a good thing is just TOO MUCH! Bottom line, you want a clean, dry rifle to start, and if you give it a spit patch every so often, you can shoot it all day long!
Personally, I use hot water, Butch's Black Powder Bore Shine, lots of patches, then Barricade, then turn the rifle muzzle-down to drain-out any excess oil. It always goes bang, so I must be doing something right!
Dave