I did 3 interviews in total: 1st: with hiring manager and a colleague 2nd: task to hiring manager and a colleague 3rd: meet with director of the team (this was after job offer was pretty much confirmed)

Took very long. I was originally hired as a temp employee and I think this was part of the reason. Almost gave up on the opportunity because HR wasn't getting back to me. The interviews themselves were good. Met with 4 people over two days in addition to a phone interview.