Pros
Will hire basically anyone with a pulse. This is a great place to break into the start-up scene. Some people are nice. Casual dress-code. Flexible hours if you work for the right manager.
Cons
The pay is awful. You can get paid double in virtually any position at another start-up. The product is horrendous. Constantly broken. Tech debt is crippling and no one is interested in fixing it. The product team is filled with self-important jerks (even more than normal product teams) who have no interest in actually improving the experience for the customer. The tech talent is pathetic- there are virtually no talented programmers on the team. It's a cliquey frat-house type of environment. There is obvious favoritism on the part of certain managers. There are almost none of the "start-up perks" left. Did I mention that the product is awful? Quarterly releases should come with a xanax for every person at the company.