I was on vacation traveling to Texas and Chicago, and now I am back, finally. This is a bit old, but I remember reading this in my friend's room a couple years ago. Here's a choice quote about Bun's approach to rapping:
BB: Well, the first thing I do is I try to listen to whatever rapping is already on the track. I listen for cadence and melody to see how the track’s already been written, and to make sure that whatever flow or flows I decide to run with, or patterns or melodies that I decide to put into the song, that they’re not already in there. Then I try to see if there’s a different part of the subject matter that I can talk about. If there isn’t, I try to see if I can analogize it, break it down, flip it another way. If that can’t be done, the best thing I can do is pretty much out-rap the guy. And when I say out-rap the guy—say, if he uses ten syllables in a line, I’m going to use fifteen. If he uses fifteen, I’m going to use twenty, twenty-five. If he’s rhyming two or three words within two bars, I’m going to rhyme four or five words in two bars. I’m going to out-skill you.
Here's another one with ?uesto, and if you search the site, there's a lot of other great interviews. Why so few hip hop magazines don't try to get these great interviews is beyond me. Especially since the people writing the interviews in The Believer write for all of the hip hop publications.