Open plan offices and general lack of a quiet, contemplative, professional working environment is the hugest con to me, even huger than the compensation issues pointed out by other commentors.
I would look to start-ups to be leading the effort to improve industry practices for software development ergonomy and human-centric working spaces (i.e. focus on privacy, quiet and individual customizability).
But instead, start-ups often try to conflate “collaborative spirit” with some shallow and false idea that collaboration is equal to being continuously embedded in a real-time stream of preemptible audio and chatter.
Headphones, jabberboxes, telephone rooms, limited freedom to be remote — none of these are useful and none address the underlying privacy and human centric ergonomy points.
Practically the only thing left that can convince me to take the risk of a startup, with its lowered compensation, poor insurance, and the poor risk characteristics of equity, is giving me my own private office, and making sure everyone on the team who wants one also has one, from the summer intern on up to executives.
If a start-up cannot offer a private office, then the start-up has to offer me the same market rate salary, bonuses, insurance and work-life balance that any other company would have to offer me.