If we're strictly talking pop songwriting, its 50. He had incredible earworm songs with hooks, bridges, adlibs, raps that had a whole direction and construction that he executed perfectly. His best lyrical performance is the Power Of The Dollar album, which is more influenced by Nas but its still not beating Jay.
Jay is just better at writing clever lines and getting a whole mission statement across in a song. He had to get singers and other voices for his best hooks, but even then thats a skill that he knew where he lacked and knew how to fix it.