Maicon is light years ahead of Evra. Its not even a close call imo. If we're looking at pure impact on the game. Maicon is a brilliant crosser of the ball, and his technique is much higher than Evra. they're pretty close in terms of dribbling and running with the ball. But Maicon has end product that evra doesn't have. I'm not even going to begin to compare who the better defender is. the way i see it, theres no way the two are equal.
If we're going on individuals, the two teams are actually pretty close. Inter have the better keeper and the better fullbacks. If you take Vidic out of the equation, then they'd be pretty equal in central defense. Inter have the better defensive minded mid's as well. but Man Utd are better in the attacking midfield department and in the strikers department.
all in all, i think Man Utd edge it in terms of players, but only slightly, simply due to the fact they have more match winners on their team. C.Ronaldo, Rooney and Berbatov all can be match winners on their day.