Pros
Leadership: the CEO is a scientist, gets into the details, but also remains hands-off, after she sets her standards: that we deliver high quality work. As contractor the entire team was very welcoming. It's the classic start up where the number of people who just want to do the work far outnumber the people who are less interested in the world and thrive in corporate bureaucracy. Gave me a positive impression of start ups. (But it's all question of leadership.)
Kontras
Like any start-up biotech with a limited number of assets, if they don't work out, chances are you'll be looking for work again.