Pros
Sounds cliche, but the people are the biggest pro. PP attracts excellent talent. I've learned so much from my colleagues and I learn from them every day. It was easy to move on in your career if you work hard, lately that has changed considerably with the upcoming merger. That said, it still remains a great place to start your career.
Cons
There can be a lot of red tape when trying to bring about any change. A company re-org and a merger announced in the space of a few months was a lot for staff to take on board, it's damaged the atmosphere considerably. People have been promoted on the basis of politics and not skill. Hopefully things will settle down once the merger is consolidated and management are less distracted. It is harder for women to progress in this company.