he's basically a street thug, brought out by eminem to make the white kid some money. He's all image.
Personally, i think he's horrible. I agree, little to no sense of timing, and his songs are obviously aimed at the teen-girl ears. Then again, many other pop sensations (especially millie vanillie)prove that you can make millions with no talent whatsoever.
To find a good rapper, go back 10-15 years or so... or look at someone like Jay-z, who never writes a single lyric down... he just walks into the studio, and belts it out.