One of the greatest that's for sure. He's innovator and evolves with every new release. 808's, MBDTF and Yeezus are all completely different from each other and well...ahead of its time.
Nope, he's one of the most overrated artists ever, his whole career is build on his early releases which were his best works and that's it. Now they call his abrasive behaviors on and off stage artistry, but it just bad manners. And using auto-tune isn't art.
He's certainly up there.