Two 30 minute phone calls followed by one 4 hour on-site interview. The whole thing took place over about 2.5 months. The 30 minute calls were standard screening calls but the 4 hour on site interview was kind of oddly formatted. I was supposed to have 3 one hour interviews with Senior Consultants and one hour long interview with the hiring director. The hiring director was out sick that day, so they just had me interview with a fourth Senior Consultant. Everyone was welcoming and easy to talk to and there weren't any overly intense lines of questioning - just questions about my experience and how I think that fits with the position. The odd thing was that it was basically the same interview four times in a row with four different people. There didn't seem to be any coordination between interviewers.
The first interviewer gave me about 20 minutes for questions about Summa, which I appreciated and thought was more than enough to ask typical pre-offer questions. The next three interviewers told me that they were sure the other interviewers preceding them just asked me questions about my self, so they gave me 30-45 minutes each for questions of my own about Summa. This mean that my four hours of interviews consisted of about 2.5 hours during which I needed to come up with questions about Summa. I certainly had questions and appreciated the opportunity to go into more depth, but I think it's crazy to expect interviewees to have 2.5 hours of questions prepared for a 4 hour interview at your company. I honestly don't think Summa intends the 4 hour interview to be formatted this way, I think it was just a by-product of the interviewers' lack of coordination.
With that said, I thought the interview still went well and I left with a generally positive impression of the company. Unfortunately, like some of the other folks mentioned, I never heard back about the position. This was kind of a letdown considering I spent so much time in the interview process. It's a minimally decent thing for employers to notify candidates of their interview outcomes.