Brutus' speech was meant to ease the crowd out of their hatred for him and the other conspirators for Brutus didn't want the Roman people to break up into an uproar due to Caesar's death and he did this by attempting to explain why his actions were for the good of Rome, however, Mark Antony's speech was meant to get the Romans into a mob mentality so that they chased after the conspirators. While the two speeches differed they were alike in ways that
they were to explain to the Romans what had happened to Julius and what was to happen afterwards, Brutus did this by telling the crowd it was him and others but he did it for the good of Rome while Mark Antony explained to the crowd how the conspirators had mercilessly killed Julius, even if it was for the good of Rome the conspirators still killed the Roman leader.
Brutus and Mark Antony may have both been equally close to Caesar, however, one chose a more antagonizing way of dealing with the leader of Rome besides Mark Antony's way of convincing Caesar that bad was to come. No matter whose would have worked, Caesar died and there was now a new ruler of Rome.