Agreed, for a short presentation that was one of the best speakers I've seen, he mentions he works at a university in front of students so perhaps he is comfortable in front of crowds and that combined with his obvious passion for the subject shines through.
Wish I spoke that well, I'm not bad anymore but I'm also not that fluid.
He is a very good speaker and got me excited to try to do some of this with my 9 year old daughter.