Getting the first call with them took a long time. A recruiter reached out initially but then didn't respond for a week or more. After an initial screen with a recruiter, and then taking the first take home, I tried to contact the recruiter, the email bounced meaning they had been 'disappeared'. I wasn't told till after the on-site 3 hr + interview hat they have a second 3 hour+ on-site, then a phone/video call with the CEO. This is reminiscent of a very early stage startup though they started in 2012. Being an active candidate is already hard enough, companies should keep the process concise and spread over few days/visits as possible, meaning do one on-site, not multiple.
I passed the take home tests, as well as first on-site successfully. It was going to move on to second on-site when they called me and told me another candidate had been chosen, the day before the second on-site.
TL;DR: Poor communication on the part of the company, broken testing process, didn't take responsibility, avoid.