Pros
Pfizer's compensation is one of the best reasons to work there. They typically pay higher salaries and have a much better benefits package than equal jobs in other companies. The higher compensation has the added benefit of drawing a wide range of fairly qualified people. The colleagues I work with are generally very intelligent and understand there job responsibilities. The benefits -- medical, dental, vision, insurance options, including the potential of signing up for a legal plan -- are excellent. They are also much less expensive than other places. (It pays to be big!) They also allow the flexibility to choose from different options to tailor your own coverage.
Cons
The high compensation has some downsides. It tends to attract people, who are very educated and intelligent, but who don't necessarily have the impetus to work as a team. At least in the location where I worked, there tended to be an "every man for himself" attitude. Furthermore, many people who had been there for a number of years felt entitled. The attitude extends to promotion practices and opportunities for growth. Pfizer touts there "open job posting" system, but in my experience this is only a cover. Decisions on promotions and new positions are made by a few people and are often based on who you know, not what you are qualified for. The open job posting system also allows for managers to "wash their hands" of any responsibility in promotion or development of their employees. While I agree that it should be the employee's responsibility to manage his/her own career, many employees don't have insight into what other positions really mean or what they might be qualified for -- especially in such a large company.