I decided to ask this question here because it had to do with tailbacks, and I didn't want to create another thread.
I'm very biased towards Peterson, because he was more or less the "sports idol" of my childhood. So I would like to say that he's in that top tier as well. However, he's very much a boom or bust runner, who was prone to putting up a bunch of games where he'd be totally ineffective outside of a long run. Although 2012 was a huge outlier in this regard. His vision was also somewhat suspect. From what I've seen of Walter Payton, Sweetness was much more consistent, even if he wasn't quite the athlete that Peterson was.