Avantages
One thing they do do a good job of is attracting amazing talent. You will likely be working amongst some of the smartest people you've ever met. It's too bad that they don't treat these people well.
Inconvénients
There is a complete lack of transparency - major leaders in the company disappear without a trace with no communication to anyone. Those that finally take a stand and quit are painted in a negative light. They do not care about creating a good, healthy company - only about creating one that gets a high valuation for their next round of funding. Everyone comes on believing they are part of something special, and then quickly realizes that they are just a cog in the wheel. No one has time to mentor you or care about your future aspirations; expect a job, not a career. As far as startups go, they try very hard not to be perceived as one (see fancy office and fancy titles). However, they still underpay many of its employees and the typical startup problems still exist, such as lack of structure and guidance. Additionally they approach the business as if it were a corporate bank, as many of the leaders are from the world of finance. If you are a creative or have a background that does not include a consultant firm or Harvard Business School, you are considered a "B" player.