Compensation/Salary, by far. You will be expected to work/travel day/night/weekends wearing multiple different hats. As it is a start up environment, it’s usually understood that your salary will be less than market rate, however, for this you should be compensated on the back end. There was none of this. I don’t regret anything and consider it a stepping stone as I learned a lot but you need to be able to afford to live at a minimum. The expectations vs salary were totally unrealistic.
*l can only speak to my experience, this may have changed*