I think Biggie is the better artist all things considered. I see posters saying Biggie only has storytelling and his voice over Jay, but there is much more than that that makes Biggie a better artist. What makes Biggie a better storyteller? The images, the emotion, and the detail. He created these characters that became a part of Hip Hop in a sense from Dark Skinned Jermaine to Arizona Ron. He had people really wanting to know which NBA player he robbed and bedded the girlfriend. Ready To Die isn't just some hyperbolic gangsta tales, it's the journey through the mind of someone that has sunken so low in life that they want to end it all and actually embraced going to Hell. Yes, it sounds sick and twisted, but as a listener, even if you shook your head in disgust and disagreement at some of the lyrics and content, it still bumped. Then he came back with a double album that was still dark, but had a bit more polish.
Jay Z is a GOAT, but what he lacks in emotion and detail, he makes up for with wit. Not saying wit isn't powerful tool in his arsenal, Jay, as great as his albums are, never quite brought it all together like Big. Jay Z attempted a double album and even if you feel Life After Death is overrated, it's still better than Blueprint 2. Jay tried his hand at the whole jiggy sound and it yielded more filler than what can be found on either disc of Life After Death. Biggie's lines are still being quoted by other greats and used as hooks to songs.
That said, at this point, it would be crazy to still rank Biggie over Jay. Biggie was elite for 4-5 years. Jay's been elite for longer. We've seen him fall off and come back, fall of and come back time and again. So yeah, Jay ranks above Biggie even though I feel Biggie is more talented.