Haha, all you people are sucking on ronaldo's bollocks, but what has he done? He has contributed very little to the team. All he does is dribble around and waste time. United have been getting by on squeaking ahead in crap games. Ronaldo simply isn't all that - right now anyway.
Mathis would be strange. There are any # of players currently in America that I think might eventually make the cut on a high level club (Ricardo Clark, Edson Buddle (best pure striker in America when healthy, Damani Ralph, Carlos Bocanegra, Landon Donovan)... but Mathis isn't one of them. Two years ago... I might have said otherwise, though... so who knows. Richardson looked excellent in the 1st CL game he played in, mediocre in the 2nd... and in the games I've seen him in since, I think he's looked quite good. Richardson would be starting for quite a few teams in the EPL, I'd wager. He can already dribble very well, and seems to be able to cross. He's just not very strong. Also doesn't seem to like to track back.