I had two phone interviews and then they flew me to SF for a half day of on-site interviews. For the phone interviews I spoke with the engineering manager and the VP of engineering. The calls were positive and energetic. The technical questions were almost too easy with the exception an open-ended question which seemed like it wasn't very well thought out. Once on-site, I met with the CEO, the two people I spoke with on the phone, and 3 or 4 engineers. Many of them looked as though they had been up all night and two complained to me about how many people they had to interview that day. The technical questions again were all around easy and it was clear that the technical hurdles the team was facing are exactly the kinds of things I've solved in the past. Aside from the couple of negative things I mentioned, everything seemed great and it appeared to me that I would have fit well as part of their team. In the end there was no offer made, but it was an overall good experience.