Went Hunter here, but still not sure how I feel about him over the other guys - pretty close IMO
I think the difference in my mind between Hunter and Helu is the impact they are gonna make off the bat. Hunter is gonna have very minimal value this season, probably next season also, and maybe even the one after that. He'll be a spell back, third down guy, and a second RB to Gore until Gore either gets traded/leaves, gets injured, or declines enough to have him in.
Helu will most likely compete right off the bat for a starting job, and probably has a good chance at landing it as well. Shanny loves them mid round backs. He'll probably be an RB3/4 type if he wins a starting job and be helpful in depth, bye week fill in, and trade fodder etc.
I'd go Helu if I was in a position to be more competitive, Hunter in a position where I was still in a season, to two plus seasons of rebuilding mode.