A total of 8 hours, over 3 sessions. 2 hour phone interview. 3 back-to-back interviews on site, then a followup chat with another of the more senior engineers. The process for me was fine. Joining at a senior level its to be expected that you don't get the job off a one hour interview. The staff I met were very pleasant, from my perspective it was a two-way process; do they want me to join and is this a company I want to join. The facilities they provided me with the opportunity to do some white-bording, I find it easier to explain ideas in pictures sometimes. Very positive process.