Contacted via email from a recruiter who found my resume online, set up a 15 minute phone screen, had a 30 minute phone interview the next day, and then flew out to the Chicago HQ two weeks later. The on-site interview was not difficult, but it was LONG. First, an hour long tour of the facility, then 4 back to back interviews. Technically the lunch was "not an interview," but it definitely was. Unclear what they wanted, I basically was just asked to go over my resume four different times. No real tough questions. The office was creepy and pindrop quiet, no personal effects. Felt vaguely like i was in the matrix.