I give the edge to Unga because he was a workhorse back and had over 40 recs in 2 straight seasons to go along with 3 straight 1000+ yard rushing seasons. Jamaal would be a close 2nd because he was highly productive as a rusher and rarely fumbled but he did have some injury issues that caused him to miss parts of two seasons. I put Staley at 3rd mainly because majority of his production came in one season.

With said I would be very happy with any one of the 3