Pros
There is lots of opportunity for career development. As a university graduate, I didn't have much to offer in experience but PayPal was willing to take me on and I've got the chance to do jobs that I would have never got if I applied for them externally. It's a really relaxed environment which I love. I hate the idea of having to wear suits and ties to work. I can wear the same clothes that I wear at the weekend but still be completely professional. On the whole, people are quite nice and open and you always know that you have a lot of support there for any issue you may have in the company, both professionally and personally. Lots of extra corporate benefits like bonuses, free gym, free healthcare and pension contribution!
Cons
Some of the red tape in the company can be a little annoying but this may be similar in many other large multinational corporations. I think that the salaries aren't quite as high as they could be.