This article is Sam Guzman's take on the issue of Reformed rap. Do look at the video towards the end:
After looking at this video, the question to be asked is this: Is sensuality ever acceptable if it is baptized in Christian lyrics and even motives? Whatever happened to the command of holiness?
And yes, I reject the notion that music is neutral. Certainly this is not to denigrate any genre fiat, but then the spirit behind the music is the important thing which must be evaluated, not the music per se.
Beloved, do not believe every spirit, but test the spirits to see whether they are from God, for many false prophets have gone out into the world (1 Jn. 4:1)