Pros
Good company with strong mission and values. They live and breath Market-Based Management (MBM), which are the 10 commandments, erh, 10 guiding principles by which the culture is formed and maintained. You must drink the cool-aid, which, at the end of the day, is not bad tasting, if you are very conservative, hard-working, and passionate about oil, chemicals, and toilet paper. Although not perfect, they do attempt to practice what they preach, from the top-down and bottom-up. Management, in most cases, works hard, rewards good behavior, and strives to help those who need to improve. Pay is in range for a large company.
Cons
It is not a "fun" environment. Typical huge company, slow moving. They day often feels like drudgery. Compliance, for better or worse, is their top priority -- understandable, but can be taken too far outside the context of their core business (which clearly does have regulatory restrictions.) Teamwork is mediocre (at least in Atlanta), because people aren't in close proximity. The office is downtown and extremely long commutes force folks to get out by 3:45 to beat traffic and enjoy their "real life" at home. Bonus structure is "performance based", but still somewhat subjective. i.e. "spot bonuses". Annual performance reviews are given, but not always salary increases -- not even COL adjustments.