Pros
You can't beat the retirement package. Full pension, profit sharing, and privately traded stock options. Profit sharing is usually over 10% and the stock dividends are also over 10% a year. It's a pretty relaxed place to work (at least my branch is). Huge company with tons of locations. If you want to move you can go pretty much anywhere in the US. They are pretty good about promoting from within.
Cons
The fact that the benefits are good keeps people around so it's hard to move up sometimes unless you want to move to different cities a lot. Management definitely focuses primarily on their sales staff when it comes to investing in them and training. It's hard as a low level employee like a driver or material handler to learn things so that you're more likely to move up the chain.