That's good interview. Both interviewers are well-prepared. They asked really fundamental but challenging questions. The interview lasted for almost two hours with the research questions also. I learned quite a lot from this interview even though I could not get the offer ! Good points: Be prepared and be ready !

Very quick and easy. Was interviewed while attending one of their conferences for college students a few years back. Had one in-person interview solving a coding problem on whiteboard and another phone interview with a different engineer on background and generic conceptual questions.