In Shakespeare's Julius Caesar, who is the more effective speaker, Brutus or Antony?

Antony was clearly the more effective speaker. It was his speech that drove the gathered crowd into a frenzy. At the end of his oration, the crowd had become enraged at what, he made them believe, had been a great injustice against their murdered leader. They immediately sought retribution and were intent on ripping the conspirators apart, as the following extract clearly indicates: 

Second Citizen
We will be revenged.

All
Revenge! About! Seek! Burn! Fire! Kill! Slay!
Let not a traitor live!

Brutus adopted a rational approach in which he explained the purpose behind Caesar's assassination. He convinced the crowd that Caesar's death was necessary for the survival of Rome and the good of all its citizens. The crowd was satisfied with his clinical, matter-of-fact and commonsense explanation and believed what he said. Antony, conversely, appealed to the crowds' emotions. He was passionate and drew them in by making them believe that they had suffered a deep and personal loss when their leader was so savagely slaughtered. It was this passion that fired them up. Brutus' speech, although intelligent, had been a dispassionate oration.

Antony also applied the gamut of persuasive speaking techniques to overwhelm the already jittery collective in the market place. He began by kindly asking his fellow citizens to give him a hearing by using repetition - the rule of three: 'Friends, Romans, countrymen...' He employed innuendo and subtle sarcasm, which suggested that the conspirators and their deed were not as noble as Brutus had originally suggested: 'and so were they all, all honourable men.'

The repetitive use of the term 'honourable' in tandem with, and in juxtaposition to, a previous statement eventually gave the word a hollow ring.

Antony used rhetorical questions:

I thrice presented him a kingly crown,
Which he did thrice refuse: was this ambition?

You all did love him once, not without cause:
What cause withholds you then, to mourn for him?

He used facts to prove that Caesar cared about all Romans:

He hath brought many captives home to Rome
Whose ransoms did the general coffers fill:
Did this in Caesar seem ambitious?

He conveyed an opinion which suggested that Caesar had compassion:

When that the poor have cried, Caesar hath wept:
Ambition should be made of sterner stuff:

He consistently used emotive language:

O judgment! thou art fled to brutish beasts,

Bear with me;
My heart is in the coffin there with Caesar,
And I must pause till it come back to me.

Antony repeatedly appealed to the crowds' emotions:

O masters, if I were disposed to stir
Your hearts and minds to mutiny and rage,
I should do Brutus wrong, and Cassius wrong...

He creates tension and stirs up the crowds' expectation when he mentions Caesar's will whilst at the same time convincing them of Caesar's generosity and good nature:

...here's a parchment with the seal of Caesar;
I found it in his closet, 'tis his will:
Let but the commons hear this testament--
Which, pardon me, I do not mean to read--
And they would go and kiss dead Caesar's wounds
And dip their napkins in his sacred blood,...

In the end, Antony works up the crowd to such an extent that the citizens are desperate to take revenge. Brutus' charming speech has been forgotten completely and the crowd has turned into an unruly mob that is single-mindedly driven by a lust for the conspirators' blood.