Vick and Hall grew up in the same area, but Hall didn't join the Falcons until the 2004 season, three years after Vick was the No. 1 overall pick by the Falcons in the 2001 draft. Both players went to Virginia Tech, though Vick declared for the draft the year before Hall's arrival.
Hall might be getting an up-close look at Griffin's development in the earliest stages of his career, but he didn't see Vick in action until the QB was already an established star.
So, take the "RG3 is ahead of him" business with a grain of salt. That said, Hall has been around the league long enough to know a special talent when he sees it. Griffin obviously fits this description.