First of all, great people to interact with all around. I was a initially concerned with the amount of MBAs on the team, but they had a good attitude about it.
I had three phone interviews and a half day of in person interviews with the teams I would be working with (PM, engineering, and design). The interviews flowed smoothly and were refreshingly casual and conversational. However, I felt the questions that were asked had little to do with "product" management, but were more focused around "project" management. There were no technical or analytical questions, very few product design questions, and those that did deal with product were all specific to the company itself. Ultimately I felt they could have done a better job screening for the proper role before asking me to make the trip into the office, but that's not to say it was a bad experience, just neutral overall.
For future candidates, typical PM interview prep taught in books will not help much here, instead I'd recommend focusing on general leadership and people management, and have a background that matches the role.