Burdensome and disrespectful. I went through six rounds of interviews though they claimed rounds 3-5 was a "panel" (it was three separate interviews). It included a presentation that they recommended I spend 4 hours preparing for. Throughout the conversations outside of the hiring manager and recruiter, there were lots of red flags and inconsistencies with the job description. When the recruiter called to tell me they were moving forward with another candidate, I asked for feedback. After six rounds you expect to have some sort of feedback. They rudely ended the call and said they'd ask the hiring manager to contact me. I never heard from them again. Overall the process was pretty disrespectful of my time and that speaks volumes about the sort of place/team it would be to work.