Sanders was incredible. if you needed a purely electric runner, with unbelievable God given talent that could make your jaw literally drop, then Barry was your man. Great running back, definitely among the tops of all time
But if you needed a guy who was the total package--could run on the edge, could run between the tackles, get the tough yards in short situations, goal line situations, great blocker, catch passes out of backfield, and maybe one of the toughest most durable guys to ever play the position, then you simply cannot do better than Emmitt Smith.
Top to bottom, the total package, hands down the best RB in NFL history. No one--NO ONE--did it all, better, for longer, than Emmitt did.
He's simply the best of all time. No question in my mind.