[quote=vancexentan]
I disagree with the voice and the look of his face. Ultron should have a more monotone and cold voice. He's a robot not unlike Brainiac. He could also do with less human expression on his face. It would go better with a cold robot figure like him.
[/quote]

He isn't purely monotonous and cold though, sure, some of his appearances have been that. 

He often switches to hammy, dramatic, penchant for theatrics to Cold, methodical and crazy. I think they've hit a perfect blend of that, personally.