Eminem - for his first work and considering he's a musical artist and not a "trained" actor, I thought he did a really good job.
Kim Bassinger - a very surprising role for her. I don't know that it was believable that she was his mom though. I don't know that you can feel that connection. She definitely went beyond her recent comfort level to play this part though.
Mekhi Phieffer - he was good but they could/should have made his role deeper and more than it was. I'm not a fan of the dread locks either.
Britney Murphy - I thought she was good but although she can't dance, I think she pulled off the sex scenes well. LOL
Overall, the story line was good and it kept us awake and watching.