For this type of presentation, I generally graded on a rubric. I did mark off for things like saying Um or excessive pauses. I also marked off for body language like never looking up at the audience. However, these minor things did not carry as much weight as the content. Content, staying on topic, and following the directions were the most important.
Of course, content is the most important, but other things matter too. In a real life situation, body language and clear speech will command just as much attention from the audience as the content. Dress and manner are often as important as content in a real life scenario.