Guy can spit, but he's heavy commercial. Earned all his money trashing pop stars then he mellowed down and spoke mainly bout his white trash existence. If it wasn't for Britney Spears and Christina Aguilera I'm not sure he would have had any early material. Very annoying voice, in my opinion, too. Despite his skill, I could never get past his whiney voice. But he has good connects, and while he's aging, can still deliver live (he just looked too old next to Rihanna @ Grammys though ... lol and then there was Dre, rofl ... nothing funnier than an old rapper, like an old punk, just doesn't work). Just my honest opinion.
Laugh if you will, but I like Jay-Z, Mos Def, Snoop Dogg, and Tupac Shakur, as far as big name--sometimes heavy commercial (especially Snoop, guy is a total whore)--rappers. Just based on their voice, connects, ability to spit, all that. And aside from Snoop, the other three have (had) the ability to go deep, a lot deeper than I've ever heard MM go, lyrics wise.