I hate these threads because its subjective. Jay Z fans are going to say Nas and Nas fans are gojng to say Jay Z. This will be the argument from both sides:
Nas- the beats were wack; something something HitBoy, something something Salaam Remi, something something "You Owe Me", something something "Oochie Wally".
Jay Z- music didn't age well, something something "Ghetto Techno", something something Beyonce, something something media, something something never was the hottest, something something carried by production