Ventajas
When I started at SharesPost, the company was 20 people in a small FiDi office. Company is now almost at 90 people in new offices in SF and NYC with plans to open offices in Asia and the Middle East. Management has done a good job at growing the company while keeping the culture centered around work-life balance and career development. Company events are great. Every year, the company takes everyone to Silver Oak in Napa for a summer retreat. Very swanky.
Desventajas
Company can get a bit compartmentalized as it grows so fast. I don't always know all the latest things happening in different parts of the company.