EMINEM: Bad fruit or good wine?

Whenever the subject of Eminem comes up in conversation, my friends are very divided in their opinions of his carreer. Quite a few think that his shift from amusing bastard to Self-Conscious E With Family And Hard-Learned Lessons Of Life is not a good one, and that he is now reduced to school with the bottom-feeders of the rap market. Others simply see it as a turn to commercialize his music, making it even more broadly accessible, and following the trends of modern rap music. So, has he aged badly or well? Is that Nate Dogg colab as crap as I tend to think? How long until Haley does the chorus on his singles?