Ok, let me preface this by saying that I never considered rap to be music. To me it all sounds terrible. I don't say this to insult rap, just to make it clear that I don't have the ear to tell good rap from bad rap. To me, all rap is bad, so I can't give a musical opinion here.
The lyrics, well thats another matter. We have a saying in the computer industry: garbage in, garbage out. I find nothing redeeming or worth while listening to in Eminem's lyrics. Its not the cussing (though I feel there way is too much of that too), its the violence and the whining. If I have to hear this selfserving little multimillionaire tell me one more time how hard his life is, I'm gonna scream. And the violence! I don't care if he doesn't mean it, the acts of violence described in his songs are beyond the boudries of what I consider excusable. I wouldn't mind as much if it were one or 2 songs, but his early stuff is just loaded with violent lyrics.
Look, I don't beleive people are going to run out and knock over a liquor store because of Eminem's lyrics, but why fill your head with such garbage? You can say its "just words", but words mean things, thats why we use them to communicate. If you listen to something enough, it will have some influence on how you think (whether you admit it or not). The concepts that much of Eminem's lyrics communicate are trash, pure and simple. Remember, garbage in, garbage out. In my experience, its true for people as well as computers.
I know that not all of his stuff is like this (and I haven't bothered to look at his new release), but enough it is so violent and self serving that I choose to dismiss him as not being worth my valuable listening time.