The discussion about content vs. delivery is almost like the chicken vs. the egg discussion. :-)
One issue to consider is the audience's perspective: What do you suppose they want from a presentation - good content or good delivery? Let me pose a hypothetical.
Let's say that I am going to attend a conference about using a new version of iBoard. There are significant changes in versions so the information will be critical to my success in maneuvering around the new system.
Although having both good delivery and content would be the optimum choice, which do you believe would be more important?