One of the big factors in deciding which cities to look at is cost I'm sure. They're starting with the smaller cities and moving up. The amount of red tape in cities like SF and NY must be outstanding.
Check out the average times, etc.
Try to imagine for a second how much easier and less expensive it is to deal with Austin than SF.
http://sf.curbed.com/archives/2013/04/03/navigating_the_trea... is a wonderful explanation
Realize it is so bad they have a many-page colored guide on replacing a fucking window:
http://www.sf-planning.org/ftp/files/publications_reports/St...