I've seen Manos: The Hands of Fate, and this movie has managed to defeat it in terms of sheer level of torture. The movie has no interesting dialog, no tolerable acting, and no plot to speak of.
On the upside, it does have a great many R&B artists. On the downside, seeing this movie will likely void any respect you had for them as they mindlessly ramble off about an urban Blair Witch parody. Eminem is entertaining (though redundant), so fans might want fast forward to his segments, should they find the movie lying in a gutter somewhere (a likely situation).
If there were a brick near my entertainment center, I would have attempted to beat myself into a coma to escape the grueling pain. I would award this movie 0 stars if it were an option, but instead this gets a very reluctant 1. Watch only if want a small personal hell in your living room.