Every back has a different running style. 'Best' can only be determined by tangibles like total yards, YPC, etc. LeBoeuf and Bergeron, the only 2 post season all-american backs and leaders in yardage gained in PN-G history, still rank supreme until someone accomplishes more.
PN-G has a long tradition of great backs. LeBoeuf, LaBorde, Bergeron, Landry, Blake Green, Eicher, Shipley, McGill, Wortham, Gholke (sp), Cook, Hemmings, Wright, Harmon, and many others have been very good backs. RB coach Kyle Segura may have a bit to do with success in the last 15 years or so.
Let's talk about the present and Caleb Harmon. Harmon has a great North South running style that's impressive. He runs with power, has a great burst into the secondary, and seems to have a knack for finding daylight and makes good cutbacks into open area. And the long runs speak for themselves. He's got some jets.
Very impressive RB and the results show it. If PN-G has a great playoff year I'm predicting All-State recognition. But the offensive line has to bring it every week and Harmon must stay relentless.