Interesting, didn't expect DC to be bigger than Austin as well.

Depends on what you're looking for. I live in Austin and I love it. There are plenty of interesting companies to work for, and you'll live in a better home in a better neighborhood for your budget. Austinites are generally fantastic, welcoming people. It's probably a good place for you. Here are the exceptions:

1. Read https://breakoutlist.com/. If that argument matches your motivations, go to San Francisco.

2. Do you have a (relatively) niche interest, like VR/AR, machine learning, or blockchains? Go where those companies are: San Francisco and New York.

3. Do you want to experience a city where everything happens? Go to New York.

Otherwise, pick Austin. Maybe Seattle depending on weather preferences and distance from friends and family.

It's hard to consider Austin as even a second tier startup city-- first tier would be SF/Silcon Valley and second would be NYC and Seattle.

I would be hard-pressed to come up with names of 3 successful startups from Austin, and I think most people would be too.