He's consistency both technical and funny. Plus he seems like a decent bloke overall (based on meeting him once in passing 15 years ago).
As he's no longer interested in Ruby or Rails, or at least by his own admission he's retired from programming, perhaps he'll do the decent thing and just step aside for more interested speakers to take over.
Aaron is a breath of fresh air, which is amazing considering he's been doing it for so long and so consistently.