I'll say that the accents are difficult but not unmanageable. Jaime's was the best but that really says nothing. As all three present more in english, obviously not their native language, they'll become better at it. Please don't take this as a negative comment in any way because I grasped everything mentioned. To drive the point home I was engaging my web OCD, i.e. browsing other sites with the audio in the background. If I couldn't understand a word I wouldn't have been able to do that.
With respect to getting a "presenter" versus a "guru" it doesn't always make sense. Here you had a perfect question and answer session that a presenter would either have to script or simply could not have if he didn't know the material well enough.
I'd love to see the slides or links to them in the future if they are part of the developer site. I hate PowerPoint for just a slide but with video/audio you can get certain nuggets the slides won't really go into like the question/answer sessions in this talk. The slides will invoke my memory of the conversation versus the other way around but I realize slides aren't always possible either.