I'd like USA win just because of the hilarity of it. A much stronger English team losing to its "colony" where they don't even like football all that much.
However, England is stronger and anything less than a win would be a dissapointment for them.
It wouldn't be that surprising really. USA are hardly weak. Anyone that can be the only team to beat Spain in god knows how long and can go 2-0 up against Brazil in a final have got to be taken seriously.
Not a great bunch of individuals, but very strong as a team.
I know USA is a strong team but not quite as strong as England and I would imagine losing to the "soccer players" would hurt more than losing to some random team.