Pros
I worked for Shell for almost a decade in a professional corporate function based in Houston. Overall, I really respect the company culture, the amazing people and how the company manages people. The Dutch influence has made the "respect for people" aspect of HR quite pervasive. They actually walk the talk. In Shell, you have a great degree of control over your career path. They post jobs internally and you are able to raise your hand for advancement if you are ready. I left Shell for personal reasons, but it was a difficult decision to leave the people that I met while at Shell. I would go back to Shell if my circumstances changed. Benefits package is top notch The 9/80 schedule was great way to manage work/life balance.
Cons
The organization is HUGE! It takes about a year to even understand the depth of the business and various projects. Because of its size, it can be a long career before you are able to take on bigger pieces of the business or into management, but it is a great company to get many experiences. The company has a reputation for having issues controlling cost, but the investors are pushing for greater control. Positive changes have been happening to get a handle on it.