Lil Wayne's writing credibility, let alone talent, has been questioned in the past.
Having said that, Jay-Z has a way with words that few rappers possess. He is gifted with brevity. The ability to use words precisely and consisely. 10 random people could be describing a mundane task like going to the mall to buy clothes and coming back home. Jay's way of saying it would stick with you and you could recite that phrase years from now, using it in your everyday life. He's instantly quotable, never has to try too hard to sound smart. He's the Leonard Cohen of Rap.
Dude could have been a Novelist or poet if he lived in simpler times.
Lil Wayne is on the exact same rapping level as Eminem. You can hear they're just rappers trying to rhyme words with each other for the sake of it.