Pros
You can have a major, positive impact on a huge number of people while learning from an extremely talented set of peers. The company operates and succeeds by listening to ideas from anyone and everyone, internal and external, then weighs trade offs and make product plans. They are also willing to change product plans as needed to strive toward customer satisfaction and adoption. Although multiple releases may be needed with a specific product to really hit a successful stride, the persistence and investment made by the company often results in great success for the company and consumers alike. The effect you can have on a large number of customers to improve their efficiencies and enable new scenarios is simply amazing.
Cons
This is also a positive, but one downside is that it is so large it is possible to feel lost.