Most of these other reviews hash out the interview process pretty thoroughly, so I won't go into it again. But I will say that the entire process was extremely long due to the stages of evaluation, but pretty efficient. I never waited more than a week to hear whether I had advanced to the next round. Overall, people there seemed friendly and happy to be there. Though I went there on the fence about the position, I walked away with a better impression than I got from the reviews on Glassdoor.
I would say that of all the parts of the interview, I was most nervous about the presentation and I know that it showed. If I were to do it again, I would do it on something more casual rather than the more complicated/intellectual topic that I chose.
I think my only issue with the entire process was that my recruiter seemed incredibly young and inexperienced, so I found it hard to connect with him due to an almost overbearing professionalism. I found out later, thanks to a couple insiders, that he had only started in June and that I was his first recruit, so I think he may just have been nervous.
In the end, they must have decided that I wasn't right for the position, but really, I can't complain. Like someone else mentioned, even if they didn't extend an offer, it was a free trip to Madison and a good chance to practice interviewing.