Pros
Good repuation in marketplace. Top of the heap as far as transportation companies are concerned. Stability. Excellent marketing machine. So many tools and resources it's almost overwhelming. An 800 support number strictly for sales (It's not perfect but it does help to have a dedicated line to call when you are in a pinch). Good customer service. Also, operationally the service IS very good. Depends on your boss, but overall there is job flexibility and personally I feel like I am treated with respect - like an adult.
Cons
Like many companies, it pays to be connected. There are many "lifers" here. Senority and relationships do play a role in who gets opportunities/promotions. Which is fine and the way things work but they make great efforts to put on the appearance of being "neutral". Benefits are not as good as you would expect from a Fortune 500 co. either.