The interview process for Agile IT was extremely thorough. There were four phases, It begins with an aptitude test and personality assessment. Both were fairly straightforward. I didn't finish all the questions on the aptitude test and I just answered the personality one as honestly as possible.
After this they have a recorded video interview session where you are asked a question, given two minutes to think about your answer, and then you have two minutes to response. Your responses are recorded on video. I noticed some complaints about this step in other reviews, but honestly it's a good way to get the "basic" interview questions out of the way -- questions like "Give an example of a time when you failed and how you handled that failure" or "Name three aspects of company culture that you think make for a healthy working environment". They are typical interview questions that do not relate specifically to the roll, but give the company a better idea of the type of person you are and if you will be a good cultural fit before they start investing resources in actually vetting you.
After this you will get a call from someone at the company. I believe it is generally the person that manages your position. The phone call doesn't take long - maybe 30 to 45 minutes. This is where they will actually vet you a bit and make sure you know what you're doing in your particular field. They'll also tell you a bit about the company and your roll so you can decide if the company will be a good fit for you before the final phase of the interview process.
The last part of the interview is an in-person, sit down interview. This interview is very thorough. They will call in the various people you will be working with to ask you questions. It takes a few hours. I can't speak for other positions, but for the position I interviewed for, the first half involved mostly 'cultural' type questions. "How would you handle this or that?" and simple role-play scenarios. The second half was some pretty rigorous testing to ensure that I was competent in my field. It included questions that were meant to put me off-guard and see how I responded, as well as some some questions to see what I didn't know.
Overall, I was very happy with the interview process. I felt like the initial phases were tedious, but they do their job of weeding out people that aren't committed to getting this particular job. I also left the interview thinking since it was so thorough, that should I get the job, I would not only fit in with my future colleagues, but that everyone I would be working with must be smart and competent as well.