Avantages
Everyone is talented (read: smart) and energetic, including the non-technical team members. As with most startups this size, there are virtually no politics. There are even virtually no technical "religions" espoused by the founders, being mostly a meritocracy.
Inconvénients
Perhaps not entirely inappropriately, it's amateur hour. For someone with experience, it can be frustrating to see basic mistakes being made, like premature optimization concurrent with delaying investment in infrastructure until there's a "fire drill" every week. The facilities, lacking hot water, air conditioning, or ADA compliance, as well as administration and benefits, reflect a similar leanness of competence. The technical work is boring for all but the most junior engineers, as evidenced by a high turnover rate of the early non-founder technical employees.