Pros
If you are an employee without a product, there is a large amount of freedom. (However, most people are not.) The pay is reasonably good, and there is a very large acceptance of gigs on the side. This is a good place to put in the minimum workload, get a salary, and build your own startup. There is a fair number of frustrated employees who do exactly that, making PayPal an excellent place to put together a startup team.
Cons
PayPal has a tradition of documenting code poorly, and of performing reorgs every 3 years. This combination makes it almost impossible to change any code: you probably cannot find anybody who knows what the code does. If you find that person -- or if you are a person who knows what the code does -- then the process of getting approval to make a change is tedious, and again, frustrated by occasional reorgs. People working in Austin or Scottsdale are often more frustrated than those in San Jose.