Ventajas
Casual environment. Good work-life balance. Some friendly people that you can really get along with. The CEO is an approachable person with respectful manners.
Desventajas
There are no experienced developers. Everyone there joins a graduate without any previous industry background. This enables maintaining the illusion that the CTO is the greatest and only experienced developer in the world. Illusion that he believes and allows him to look down on everyone else. There is a toxic culture coming from the top down where you either win a few p****** contests to become a "genius" or you will be deemed intellectually inferior. The whole company sails on the CTO's mood swings, alternating periods of absence vs micro-management, and erratic decision-making. Every issue that I've seen arise was faced with excuses and not dealt with (proof of that are the fake reviews in Glassdoor). You learn poor software development habits.