Pros
Most employees are generally given a large amount of responsibility. You will do a lot and learn a lot. The company is on solid ground and should be financially fine for a number of years to come. The campus is nice. It's good to know that your are working on compounds that will actually go to market and help people out. If you can survive it you will have made money on the retention side (stock/rsu/espp). I'd say about 50% of new hires don't last more than 2 years.
Cons
To get ahead you are expected to work any day, any time at a moments notice and be 'committed'. For the most part, that's how the company works and that is what is expected to be in management. This leads to a very high burn and churn rate of employees. A lot of knowledge and experience exits the door. Expect to work while on vacation. Your line management constantly changes. It is difficulty to get any traction with your career. When your department management changes yearly, the goals and vision changes as well. Much of the time is spent in management transition periods. The daily work is high paced and projects are understaffed. You also have to seriously watch your back at all times.