The CEO reached out to me which was cool so I took a call and liked what I heard. Had an initial phone screen (introduction to the company and culture), and a second screen by a recruiter and one of the BD people (behavioral questions mostly). I liked the intellectual thought put into the questions, these guys definitely have their interview process somewhat nailed down.
After two weeks I was asked to fly down to their HQ, the process of booking took slightly longer than I expected, but eventually showed up on-site. Mountain View office was smaller than I expected, but sufficiently comfortable for the team. The interviewers were well coordinated (except one) so things were on time and there was very little question overlap. Each one was 45 minutes with sufficient break in between for me to catch my breath. Questions were mostly behavioral and personality type with some sales / organization skills ones.
The hiring manager was definitely excited about me, we went out to coffee together and talked about my hobbies, passion, and career plans. By then I knew they were interested in moving forward -- two days later I got a call from the recruiter and they made an offer which I accepted (comp was reasonable).
Overall, I liked that the CEO reached out to me, he sold me on the opportunity. The interview process was sufficiently fluid minus some awkward silences (with engineers). The company is a startup, people work long hours, and there are growing pains -- none of this was hidden from me, they did a good job of communicating that. Would be on the top 25% of my interview experiences.