Banks got the edge in wit, punchlines, all that
J. Cole got a broader range of flows
Banks can be annoying with his raspy delivery but J. Cole also got that little corny "clear your throat" rapping sometimes.
I'm not gonna pull out verses and compare them side by side to say who's got better rhyme schemes or all that, but I imagine J. Cole would.
As far as storytelling, its very even. The stories on The Warm Up and songs like Lost Ones are definitely no joke, but HFM and etcetera got some good stories as well.
However, I would say Banks has a more polished rapping ability compared to Cole's. And if you want to talk about things other than rhyming, I would say Lloyd Banks has more charisma. Say what you want about Cole as a producer but his beats are on point, but I would say that category is even between Colely Cole and Banks.