Over the last 10 years, the Bills have consistently had running backs who have had 1-2 great seasons, but could not sustain it. I am not saying that McGahee falls into this category, more saying that we should be more cautious.
Not since Thurman Thomas have we had a truly consistent RB. Players like Holmes, Smith, Bryson, Morris and Henry fill my minds with potential based on a few seasons, but ultimately never panned out. I am just a little reserved about McGahee until I see a full year as the #1 back, and probably 2-3 yrs of consistent production.