I first had a screening interview (approx 15 min) with a recruiter on a Friday, who at the end of the interview let me know that she wanted me to have an interview with the manager who this position directly reported to. This interview was general screening questions and a few technical troubleshooting questions. I got a call within an hour of this screening interview to set up the second interview, which we were able to schedule for later that same day, also by phone (approx 35 min). This interview was more in-depth about my experience and what I was looking for in a job, as well as more technical troubleshooting scenarios.
The following Monday I got a phone call letting me know that the afternoon interview went well, and that they would like to have me into the office for a power round of interviews later the same week. It was about 3 hours of interviewing start to finish (tour of office included). The interviews (a total of 5) were with groups of 1-3 current employees ranging from team members, managers, and the director of the department as a last interview.
Everyone was really friendly and made me feel comfortable, the in-person interviews were more conversational than formal, and I could tell that they wanted me to succeed (ie. no surprise questions or particularly difficult questions, but definitely some that made me think long and hard). There was a strong emphasis on culture and making sure I was a good fit personality-wise as well as my technical skill. Also an emphasis on being a quick, willing, and able learner. Overall extremely positive.