I mainly listen to underground rap, and most of the MC's could rip any beat so much better than the "mainstream" rappers
The current state of rap that is considered "good" enough to be popular is ridiculous
Army of the Pharaohs is a good example because it is a collaboration of different underground artists.
If you like good hip-hop/rap, check it out.
http://youtube.com/watch?v=cASLfP6mkC0&feature=related