It also depends on how do you think it is the best for your students to learn : By listening (hopefully carefully) to the course, and then reading notes you'll provide them, OR by letting them write themselves the content.

I don't like to much the first option, certainly because I've not been used too, and I believe it is a huge advantage to write yourself everything at the moment, because of obvious memorization advantages (it was important for me to have my own notations, a kind of taming procedure) and, once you read your notes again, you usually remember where was the parts the teacher got enthusiastic.

Considering then the second option, it is for me an evidence that blackboard win :

• you give the time to the students to write since you do it yourself
• the statements stay longer (at least if you have enough blackboards, or just keep the main Theorem on !)
• there is more interactions content-author-students
• your eyes are not constantly dried by this terrible white light
• it allows improvisation
• it is more classy (personal point of view, I agree)

Against :

• it is suicidal (that is terribly soporific for the students) to NOT prepare a lot your presentation, at least as long as you should spend time one slides
• it requires a good handwriting from the teacher
• its not convenient for drawing complex pictures

My conclusion is then the same than André Henriques !