Benson is my age. We were in HS at the same time. The year we won state was one of the years he won state. I have watched him run since literally his Freshman year in HS. Every HS team feared Benson, with good reason.
He has the most important aspect of any RB - vision. He has good enough speed, he is strong enough, and good angles. I will eat crow if I am wrong, but, barring injury, Benson will be a force for many years. He may not be a flashy runner, but he averages good, he can be a workhorse, everydown back, etc. Any team that drafts him will be very, very lucky.