The interview process was somewhat long but very thorough. The initial phone screen was about 30 minutes or so followed by a "technical questionnaire" over email, an online (zoom) technical interview and a series of on-site interviews with lunch.
They flew me to San Francisco for the half-day on-site interview which consisted of a short technical exercise followed by the standard trick "googlesque" technical question. The short lunch with a member of the infrastructure team seemed to go well although he did most of the talking and didn't ask many questions of me.
I was told the technical interviews would mainly consist of systems and infrastructure questions but they were closer to what I would have expected for a Software Engineering position.
The team seems awesome and they certainly have that San Francisco the company flair.