I will suggest picking option 2. Executive position and title at an established company (assuming relatively well known company in segment) will go a long way i

I will suggest picking option 2. Executive position and title at an established company (assuming relatively well known company in segment) will go a long way in your future executive career growth. I wouldn't be surprised that after staying in the role for 6 months, you will start getting contacts from executive recruiters for executive positions at other companies. Also, being in executive position you will most likely interact with BoD and other investors. At exec level, you need connections to move up and sideways. The chance of B2B startup becoming big and stay independent are low. Most such startups get acquired by larger established companies in the segment. Executive position at startup doesn't typically equate with executive position at acquiring established company. As a non-exec at startup who might have been reporting to an exec at startup, you most probably will be demoted and reporting to someone non-exec in this situation at acquiring company. You will lose any professional cachet in executive recruiting or moving into executive role.