compare common to most main stream hip hop. a better statement may have been that common is a lyrical genius in comparison to most other hip hop artists who have made it big enough to be considered main stream.
for example, common is a lyrical genius when compared to artists such as yung joc. It takes little to no intelligence to write lyrics about being in the club and making up stupid ass dances to go along with your video. Meanwhile common is able to display women in a respectful way and to highlight their beauty in the "go" video while also writing lyrics which are clever and very intelligent.
to underground rappers, maybe common is only decent in your opinion...and i respect that but think about how he is pretty mainstream among a sea of "in the club, cris drinkin, surrounded by hoes and bitches" other rappers. gives him some credibility ya know?