Maroney was my favorite Gopher RB ever, he was a very tough physical RB and could just blow past people in a very AP like way. I recall many plays where D backs took an angle to tackle Maroney, only to end up diving and missing because he covered so much ground so quickly.
MBIII was my second favorite gopher back, as he was always a shifty and tough runner who finished runs in a very physical way gaining extra yards. He also could break long runs despite his lack of a top, elite gear like Maroney had. I always though Barber was really good, but only when he became a star at Dallas did I realize that how great he was. Barber had the best NFL career of any Gopher RB ever (as a RB if you dismiss Bronko N.)
Brooks and Smith are as close to Maroney and MBIII as any backs since, and certainly could be almost as good since they are not done yet. Neither is as fast as Maroney or as physical as Barber, but both have some unique strengths. Brooks is almost as physical as Barber, but he is shiftier and probably a little faster. Brooks is probably has the best all around array of physical skills as a runner as any of the four. Brooks is stronger than he looks, but he has incredible vision and high end speed. Brooks can shift and accelerate very well, but Brooks can do some very deceptive things without losing his speed and will make the defenders look foolish.
I am not sure which one is better, but I hope they both get a lot of touches each game.
I was concerned that Fleck referred to McCrary as the "third down back" in an interview with Paul Allen this week. McCrary better only see the field as a change of pace back, in the case of injury, during blow outs, or in short yardage once in while, but never as player who comes in during every third down. I cannot stand the whole NFL "third down back" mentality.
https://www.youtube.com/watch?v=tR_aN0qg--g