Prezi is awesome, isn't it? You can create twists and turns, zoom in or zoom out, create interesting paths for your audience to follow as you wow them with quotes in parentheses and tiny little asides in the dot of an I.
Perhaps it's my visual learning style that's getting in the way, but when I watch a Prezi, I find that I'm distracted by all the bells and whistles. I start trying to predict where the Prezi will spin to next, and lose focus on what the presentation is actually trying to say.
Perhaps I need to play around with it a little more and get to know some more features. Or maybe you can help. Other than the fancy animation, what can Prezi do that PowerPoint can't?