The interview process consisted of three parts: two phone interviews (one with hiring manager, one with a peer), and a full-day on-site interview. The phone interviews were very detailed: you had to give very precise answers about your project, and how things went exactly.
In the beginning of the on-site interview there was one one-on-one interview with a manager, then they gave you a short assignment, and you had about one hour to prepare to present it to the team. The presentation was free-for all, expect to be asked a lot of questions. After the presentation you will have more one-on-one interviews with different roles (product manager, UI designers, other UX researchers).
The UX team was very nice and professional and they make you feel comfortable. Their labs in Sunnyvale are also awesome.
However, what makes the overall experience negative are the technical recruiters. They were extremely bad and even disrespectful in their communication: they promise contact you (several times), you arrange your schedule, and then they do not get back to you. Otherwise very pleasant interview-experience, and company impressions, were ruined by them.