Pros
Never seen a CEO with such a drive to succeed. Full of smart people from a variety of backgrounds, including collaborating with teams internationally. Ability to make a direct and visible impact on the company, which is not always possible as an engineer. My team works primarily remotely, but still enjoy the office culture of a tight-knit group of co-workers and friends. Pay is ok, but like many a startup incentives are tied directly to our success.
Cons
As a startup, many processes and policies are still being developed. While pay is good, benefits are lackluster. Previous to this year, no formal process/policy for career growth and salary increases were instituted. Still waiting to see how well the new processes work, but the new performance reviews were easier to navigate than many of the previous companies I worked for. Unlimited PTO is nice, but like many a startup the pace makes it difficult to take advantage of it.