Given that nearly everyone at the conference was under 40, and that there was stiff competition not only from faculty but also from some of our other graduate students, I would say that this is quite an honor.
So, congratulations David!
Oh, and David is on the job market this year. Hint, hint.
Addendum: not sure why the web page lists David's affiliation as the University of Copenhagen. He's not even Danish.
Addendum 2: the winning paper can be found on David's web page. It is the one about the tax gradient.