Pros
Training programs, structured careers (until you complete approximately 5 years seniority) and then it is up to your ability to network or be lucky enough to get a manager who cares about your development. Good systems, knowledge management, technical careers. Diversity is motivating and probably the reason why people stay.
Cons
If you are part of the structured career there is visibility of your career progression the first 5 years. After that, even when you have systems to list your preferences and a meeting where you are supposed to come up with a plan for development, you can get the job you didn't want to do. This is not necessarily bad...but the culture is sink or swim, predatory and not much mentoring going on. The International population is tied to their work visa so they work longer hours, accept any assignment, do whatever they can to keep their job as they do not want to be sent back to their home country. Also, if you are a woman you can be favored just because they want to increase their diversity. That is not necessarily good, your peers will hate you and make your life hell. If you are American or have the freedom to go somewhere else, you will soon realize you can find better opportunities at an Oil Company and better pay, benefits and lifestyle. Schlumberger is good for learning (some people in my group would call it SLB University) but then move on. If you are a foreigner, they will not sponsor your green card. They have started to do that for some very technical people but it is random and driven by friendships with HR. Also, in support positions (Finance, HR, Supply Chain, etc..) you can end up stuck for years in the same job as there is no clear development plan. The Company is becoming so big that the "human" part is lost, people are put in management roles with no people skills or interest in developing others. Bad managers get away with breaking all the policies and rules and the ethics line is useless. It is NOT confidential and you ALWAYS end up being retaliated against. Again, good systems but they are not used correctly, there is a lot of corruption that cannot be reported.