I waited 3 weeks after being selected for an interview to meet with a recruiter. The rest of the interview process took an additional 3 weeks. I turned down another job offer in the meantime, which was a huge gamble, but I'm very happy with my decision. The interviewers were all very charismatic and attentive listeners, spoke very freely about what they like about their current alignment and what could improve, and gave me great feedback on how I could improve their very lengthy assignments. I spent over 10 hours between interviewing and doing/correcting the homework, and there was a little disorganization between the different interviewers, but this was still the best interview process I've experienced.

negative experience - strung along through more than 4 interviews - each took hours of prep time and the final interview you could tell the VP came in knowing they didn't want you. Looking for a very specific type of person.