Bain did a presentation on my college campus and is a regular recruiter there. I did my interview over the phone because I was abroad. I did two rounds - two cases in each round along with some questions about some of my experiences. I'm not sure how many people were interviewed. True to their reputation for being down-to-earth and friendly, my four interviewers were all very helpful (gave me feedback after my first round) and supportive. Definitely the type of people who would be a pleasure to work with.