I vastly prefer handwritten presentations to Powerpoint presentations, but because it's so dynamic.

First, look at content. When you're delivering a Powerpoint presentation and a great side conversation arises, you are pressured to return to the content of your slides before you divert too far. If you don't, then you've lost your visual medium for interacting with your audience. Granted, sometimes it's better to refocus, but it's arrogant to believe you can always anticipate the best direction a conversation can take ahead of time. Anecdotally, my favorite classroom memories of school involve the teacher abandoning plans for the day because students were passionately interested in a side conversation. I'll note that none of those teachers used Powerpoint slides.

Next, there's form. Most subjects are easily broken down by bulleted lists, but that doesn't mean that it's always the most effective way to transmit information to others. Some Powerpointers are talented enough to genereate lots of high-quality picture-based slides, but they're few and far between. I've met some of these talented few, and they're always clearer on a markerboard, because they are able to dynamically change their diagrams as I ask questions and comment.

I realize Powerpoint works better for some scenarios, but if given the choice, I'll choose the guy with the marker in his hand every day of the week