Ventajas
Freedom and flexibility. Bosses don't really breathe down your neck. The problems we're solving are complex and interesting. Great compensation. Management is not afraid to put people into leadership roles if they perform well. The culture is great and people are easy to get along with.
Desventajas
Legacy code bases are a mess. Upper management doesn't always communicate as often and as clear as they should. There are exceptionally busy times of the year. Recently, there was a layoff of 1/3 of the company which really hurt morale for those of us still here. With few exceptions it was a way for them to cut costs and trim the lower performers.