3 phone interviews and 2 in person, plus some homework assignments. Initial phone screen with HR - the interviewer was definitely reading questions off a list, very bland, very little reaction or engagement with any answers. 2nd HR phone screen was the same thing, with some of the same questions. The next 3 interviews were case interviews (2 related to the job, 1 completely ridiculous one). Case interviews were very interesting, interviewers were more engaged, but during my in person interviews the interviewer literally had a sheet of paper with questions and canned responses...
HR and interviewers were unresponsive and overall the process was not very professional - basically all communications went unanswered and 1 interviewer was an hour late. I flew down for the last 2 interviews, and travel was a hassle. I was not approved to stay overnight (not sure why), so I flew in very early in the morning and out very late at night which was awful.
They save the interview with your direct supervisor for last, which meant that when it wasn't a great fit between us I had already wasted a hefty chunk of time on the other 5 interviews. We both knew it wasn't a great fit, but I expected more than a form letter from HR telling me I wasn't getting an offer.