Most complete: Childish Gambino
Conceptually: Kendrick Lamar
Pure rapping: Hopsin
This place used to hate Glover, I wonder if that's still true.
But I can't in good conscience say Gambino because I value consistency. And while Gambino was my favorite rapper from 2011-2015, it was because he was always changing, always evolving. Then he dropped Awaken My Love and fucked around and evolved right out of hip-hop. He said he's almost done being Gambino and I'll be honest in saying I'd be surprised if his last project features any rapping.
As far as my answer....shit, fuck if I know. Kung-Fu Kenny rap his ass off, but so does J. Cole.
But you should ignore me, I've been bumping Hoodie Allen for the past two weeks lol. (Do You Believe...)