3 good players, still that depends of the type of the tactics you use.
Veloso, in my opinion would be the best, he is a top player in any tactic, great at passing, Heading, long shots, tacking, Marking, dribbling etc...
Palombo is algo a good player both at defending and passing, still he can't advance in the pitch like Veloso
Diarra is a good fighter in the midfield, fast, good tacking, advances well in the pitch still his heading and marking skill can cause some problems in the defense.