Pros
The company is solid. Senior Management knows its place in the global economy. Promotions to senior positions are made exclusively from within. People stay for the long term. You are still considered a new comer until you hit the 15 year mark. It is not uncommon for people to spend their entire career at UPS. Decisions are always made by a group of people and not individuals. This leads to the promotion of many ideas and different points of view. From a technology point of view (which is my field), we are cutting edge. The drive of our technical people and CIO positions the company to be successful in the future.
Cons
Decisions are made by groups of people. Sometimes you just need someone to say "We're moving in this direction. End of discussion." Office politics sometimes trumps what's good for the company.