I went to Affiliate Summit Central in Austin earlier this year and it was awesome. Austin has a fantastic downtown, but isn't super crazy and busy like bigger cities. I really enjoyed my time there and would definitely suggest checking it out Amazing food too!
I haven't been to either place. But I have met some people from both areas and if I had to choose based on these interactions, it would be Austin.
Sorry. I have nothing against either area. It's just that some people were better able to "promote" their area.