Check out this article, in Touchstone by Russell Moore on Johnny Cash, who succeeded in a way most "Christian artists" don't because they're so kitschy in their strain to be cool:

"Cash always seemed to connect. When other Christian celebrities tried to down-play sin and condemnation in favor of upbeat messages about how much better life is with Jesus, Cash sang about the tyranny of guilt and the certainty of coming judgment. An angst-ridden youth culture may not have fully comprehended guilt, but they understood pain. And, somehow, they sensed Cash was for real."