How can you think overrated about a guitarist who writes his own music, has his own style and has played hundereds of shows? Proven he can pull it off live, on stage!
His style is different from other "more complex" styles.
Try playing his solos with feeling and perfect timing, if you realy try you might realize that hes not that bad
Hes more underrated I think.
Most people say Slash and think about the self-tought guitarist who will play with any band he likes.
respect @ Slash, so I think he's great.