How was Antony's speech more effective than Brutus' in Julius Caesar

Brutus and Antony are two different types. Brutus is philosophical and rational. He wants peace and order. Antony is a notorious hedonist and fun-lover. It is natural that each man should have a different objective. Brutus wants everybody to listen to reason. Antony wants chaos. Antony actually tells the crowd that it is only reasonable to express their emotions--and he probably really believes this, since he is so emotional himself.

I speak not to disprove what Brutus spoke,
But here I am to speak what I do know.
You all did love him once, not without cause;
What cause withholds you then to mourn for him?
O judgement, thou art fled to brutish beasts,
And men have lost their reason. Bear with me;
My heart is in the coffin there with Caesar,
And I must pause till it come back to me.

Antony is suggesting that they are not showing the good judgement which Brutus was appealing to because they are not venting their emotions. He then pauses because he is supposedly overcome with his own emotions, and he is thereby setting an example.

Antony's speech is more effective because he is trying his best to stir up the crowd, whereas Brutus's speech ia less effective because he ia trying to calm them down. Antony also has an ace-in-the-hole. He has Caesar's will which he brings out and waves at the mob, and then, when he gets them to force him to read it, he first shows them Caesar's mutilated body. This is actual history recorded by Plutarch. Brutus has told the people that he loved Caesar, and earlier he had told the other conspirators:

Let us be sacrificers, but not butchers
.   .   .   .   .   .   .   .   .   .   .   .   .   .
Let's kill him boldly, but not wrathfully;
Let's carve him as a dish fit for the gods,
Not hew him as a carcass fit for hounds;      II.1

But the condition of the corpse tells a different story. Caesar looks as if he had been crudely butchered by dozens of savage, impassioned men motivated by envy, hatred, and fear. Only Brutus stabbed Caesar in the spirit of making a sacrifice.

Antony succeeds in creating total chaos. He has to do this because he is all alone against an organized group of conspirators headed by a highly respected man. Antony proves to be more eloquent than anyone, including anyone in Shakespeare's audience, might have expected. Although he calls himself a plain, blunt man, Antony comes up with dazzling oratory in Shakespeare's best iambic pentameter. It is noteworthy that Antony speaks in poetry while Brutus speaks entirely in prose. Antony is telling the mob he has no power of speech and at the same time exhibiting power that Brutus himself, a trained orator, was incapable of matching.

I am no orator, as Brutus is;
But, as you know me all, a plain blunt man,
That love my friend, and that they know full well
That gave me public leave to speak of him.
For I have neither wit, nor words, nor worth,
Action, nor utterance, nor the power of speech,
To stir men's blood. I only speak right on;
I tell you that which you yourselves do know;
Show you sweet Caesar's wounds, poor poor dumb mouths,
And bid them speak for me. But were I Brutus,
And Brutus Antony, there were an Antony
Would ruffle up your spirits and put a tongue
In every wound of Caesar that should move
The stones of Rome to rise and mutiny.

Caesar's wounds appear to be calling for the citizens to mutiny. Brutus himself seems to be calling for them to mutiny because Brutus has figuratively traded places with Antony. And finally the very stones of Rome seem to have acquired arms and legs and are all arising, figuratively speaking, to take part in a universal mutiny. There is no comparison between the speeches of Antony and Brutus. Later when the generals are holding a parley before the battle of Philippi, Cassius will say to Antony, partly in praise and partly to embarrass Brutus:

The posture of your blows are yet unknown;
But for your words, they rob the Hybla bees,
And leave them honeyless.           V.1           

Shakespeare must have coveted the opportunity to render Antony's historic funeral speech in English iambic pentameter, and Shakespeare's version was probably the best thing he ever wrote.