I applied through my college's career board, and was asked to take a personality test pretty much right away. Maybe a week later, I was contacted for a phone interview. After that I was asked to fly out to Madison for an interview; Epic covered all transportation, food, lodgings, etc. Less than a week after my interview, I received an offer. The entire process took about a month.
I thought the interview process was pretty relaxing, overall. The phone interview was very basic; they asked about things like whether I was willing to relocate, and I had the opportunity to ask my own questions. The on-site interview process was laid-back too; they devoted as much time to tours, explanations of the role, and demonstrations of their software as to actual interviews. I had an HR interview, which was mostly going over my resume and talking about life at Epic; a case study, which was more about prioritizing and common sense than anything else; and a series of SAT style tests, which...were very much like the SAT. Overall, it was low-stress, people were friendly, the campus was very nice, and I got a lot of chances to develop my own impression of the company.