He's gone from the best side in England to the second best side in Spain, which is a very large mile ahead of the opposition!
But he also crapped all over what anyone else could do in England or at the best side in England, and he's crapped all over what anyone else has done at Real Madrid easily aswell.
O'shea was at Utd and has won loads of stuff for them, if he went to Real and also won a cup, would that also make him one of the best players in the world, of course not, who you play for doesn't change how good you are, or aren't.
LIkewise bringing up world cups is laughably stupid, Pele won world cups because brazil have a very strong team and have for as long as anyone can remember, Portugal don't have a strong team, Argentina have good players, but not a fantastic team, not at all a bad team and they have a significant shot at winning something.
IF Hleb was as good as Messi, would failing to win the world cup with Belarus rule him out of being classed a great player. World cups are holy grails mostly because, its only every 4 years, and not many people can win one, its FAR harder to win, because while you can move to any club in the world to win titles, you can't move to a better national side.
Messi and Ronaldo are awesome, simple as that. Messi has a team supporting him, Ronaldo has a far weaker team around him, both get easy and hard goals.
The Messi one where he just he cut in from wide than turned away inside the box from the defenders, it was a nice looking goal and a clinical finish, but defensively it was laughable, defenders looked like deer's caught in headlights, awful positioning, awful movement, no tackling, no reading what he might do, it was a pretty easy goal but very few people inspire such fear in defenders that they make it easy for themselves.