Several interviews over the course of three months followed by an initial salary offer, only for the CEO to rescind his offer during salary negotiations. Phone screen with the CEO, followed by three technical interviews with the CTO which consisted mostly of verbal questions regarding state estimation and sensors. It was four weeks between when I was told I would receive an offer to when I actually got one. After I countered with a higher salary request (as one does during salary negotiation), I was met with radio silence for a week before the CEO told me he would be considering other candidates instead--no further explanation. Overall very unprofessional experience and a huge waste of my time.