Ranging from very formal to informal chat. First few rounds were over the phone followed by one day of in-person interviews.
Some were very structured with a list of questions that looked to be issued by HR. The key Senior Executive created a laid back environment, preferring to interview over a cup of coffee to "chat".
All were courteous. The biggest gap was with HR. They were slow to respond or provide feedback and seemed uncoordinated when it came to an offer letter.