I think it went ok? You can never be sure, of course, but I don't think it went too badly. It was just with my POI, who was very nice and engaging. It was supposed to last about 30 minutes, but ended up being almost a full hour. He asked me questions first, about why I wanted to go to this particular program and my research (what, why, how), pretty much what I was expecting. I fumbled over a question about methods, because I'm always more of a "what" than a "how" person, so I'm still kicking myself over that. And he asked about my grades, which I had been dreading, because they are good but could certainly have been better. I didn't ask how many people were interviewed, but he did say it was only a handful.
It was a very illuminating interview for me though, and it certainly put Madison higher on my list of programs I want to attend. It seems like a really stimulating department with a great work environment. I'm not supposed to hear back until early february, however. I can't say if I managed to completely convince him of how awesome and special I am, but I think I'll be on the wait list at least. (whoo?)
The one question that had been on my mind the most was "why me?", because grades/GRE wise I know there are better/smarter people (there always are) and we all want to know what we did right/wrong. I wasn't sure if it was ok to ask, but I did anyway. According to my POI it really was about fit, because my interests overlap with a lot of the faculty. So I guess working on my SOP for four months really paid off!
If there are any questions about the interview or maybe the program itself (he certainly told me things that weren't on the website), let me know!