I had my onsite earlier this week and am still waiting for a decision, but wanted to write this now regardless of the final decision. Out of my 5 years as a designer, this was one of the most enjoyable experiences I've had! I was reached out on LinkedIn by a recruiter and we had a quick chat to discuss open roles and my background. After that, I proceeded to the next round: 2 x 45 min calls for a portfolio review and app critique. I heard back a few days later that they wanted to bring me onsite. Up to this point, the recruiter I worked with at FB was friendly and thoughtful, and offered both in-depth feedback and time to do a dry-run presentation to prepare for the onsite. These thoughtful touches really impressed me, and I haven't come across that in any interview process I've had. The onsite interview was ~4 hours long and enjoyable. They were interested in my work and asked great questions, and seemed overall friendly. The 4 hours consisted of: presentation, lunch break, background (prepare to articulate your design decisions), app critique, and a whiteboard exercise. While I'm still waiting for a decision, I want to say that this was a great interview process and helped me better understand what design is like at Facebook.