I think we all agree that there are two spots for these three players and that this competition is the closest contest on the roster.
Ware offers experience, especially in pass protection.
Brown was running effectively in the preseason, with the exception of his fumble.
Scott offers something important too. Special Teams play. He blocked a punt this preseason. And was close to blocking a second one last night, which ended up being a huge penalty, keeping the Patriots drive going. He needed to take a better angle to avoid the kicker.
Personally, I thought Brown outran Ware, not only this past preseason, but in 2011 too. I predicted Brown would make the roster over Ware in 2011. However, Ware does offer better pass protection than Brown. That's why the Giants kept him in 2011 and will again in 2012.
Scott didn't get many carries, and when he did, it was late game when the third string Oline blocking was atrocious. However, I think he offers something that the other two don't with his speed he has the potential to block punts/ FGs.
So I think Brown, even though he ran the best of the three this preseason, doesn't make the roster. I don't think he is eligible for the PS. However, Joe Martinek likely will be available for the PS and is certainly eligible.
That's my two cents, and worth every penny!