If he were 5'8 instead of 5'5 people would be comparing him to Barry Sanders (5'8), but because he is so short people compare him to Darren Sproles (5'6). I'm not saying he is on the same level as Barry, but Vaughn's short area quickness I haven't seen in years in the NFL. I think he is better than Pollard right now, but that doesn't mean that he should start over Pollard, I think everything needs to be earned. I do worry about how small he is, but watching his college tape and this last pre-season game you can tell he is special. I also understand why people have questions because he will not wear defenses down ala Emmitt Smith, Zeke. One of the issues that Barry ran into is that he was not as durable as Emmitt, and he would get stopped in the back field often because he was more finesse than a pure downhill runner.
I also hate bringing up Barry after the first pre-season game, but when I was watching Vaughn I immediately felt that anytime he touched the ball anything could happen and I remember having that feeling when watching Barry Sanders. Like I said it's just a feeling not a complete evaluation. I would hold off on any evaluation until after the season then figure out where everything stands.
But if I were pressed today, Pollard would still be the starter, but obviously Vaughn would be getting a ton of looks throughout the season, because if he is what I think he is, I think that he will transform this team.