A beat Kanye West made for J-Dilla, but never heard himself (whatever that means) is creating such a brouhaha today. I think it's a banging beat, but certainly not his best. Banging, all the same. It's not being received with mixed reviews at all, most people like it. However, one commenter on XXLmag.com (L.Gunslinger, 6th comment) has the following to say:

J-Dilla was heavily over-rated. He had a few good beats, but most of his beats were just rushed 2 bear loops...That is why Dilla wasn’t rich when he died.

The track, which I remind you is banging, and a good starting point for the tracks history is available for listening here.

Secondary to the track's broululz, discussions about J-Dilla's competency in general are taking place here & here.