Overall the interview process was positive. Applied and got an email back the next day setting up a call with a current SDR. About a week later, my HR point of contact reached back out for a quick touch base and to schedule the onsite interview.
Met with 9 people in about a 4 hour span (all were planned except met with one extra sales exec) at Greenhouse's NYC office. Given a tour of the office and then asked to do a quick presentation for a small group of SDR's and a few managers. After that, met with different people throughout the day, some in groups, some 1-1 and discussed the SDR role, my background, culture, and personal questions. The last part of the interview was discussing the interview process with my HR contact and a few technical questions (when can you start, salary, benefits, other interviews you've been on) - was told they would be in touch in the coming days leading me to believe a potential offer could be sent over. I left Greenhouse feeling confident there was a mutual fit and was disappointed to receive an email a few days later letting me know they went ahead with other candidates.
The interview process was very thorough and challenging, but informative and really gives you a feel for the company.