Hi, let's discuss services for creating presentations. Personally I found of PowerPoint with good template. It's easy to use and can provide you with a good result. 
I've heard a lot about Prezi, but haven't ever use it. 
So Prezi has some advantages: 
1. Breaks the Mold
2. It's Free and Web-Based
3. Link Text and Images to Movement
4. Appropriate for All Ages
5.  Shows Students You're “Up-to-date” with Technology
and some disadvantages: 
1. Can Cause Motion Sickness
2. More of a Learning Curve
3. Web-Based

So in general i like this service and hope to use it successfully.
google presentation
prezi