I first had a 10-15 minute phone interview with the chief scientist in the group that was offering the position. He then passed me onto HR, and they arranged a formal interview. It took about 3 weeks for all the arrangements to be made. Interview at the company consisted of 30 minute interview with the HR (usual going over the resume) followed by hour-long presentation of my research and prior work in front of panel of 12 people, followed by one-on-one interviews with the panelists. Panelists ranged in their age, experience and background from old well-established scientists to young newly employed people. Interviews ranged in level of technical details from very technical to completely non-technical (If you were a tree, what tree would you be and why?). People were generally pleasant and relaxed towards myself. I did however sense some stress, hostility and negative dynamics between certain panelists.
I didn't get the offer, but I am unsure if I would want that particular job even if the offer was good.
I would love to come work for that company however, at a different position.