Pros
Challenging work, smart people. People who take initiative / take charge are rewarded. Combination of on-the-job and scheduled training, but you need to own your career. Informal mentoring is available but you need to develop a network.
Cons
Some people get lost in the work processes, lose sight of the value they are trying to deliver. Due to the hazardous nature of the oil and gas business very risk averse, slows decision making, drives up costs. Sometimes feels like decision by committee when intent is to get the right people involved in the decision, which usually means too many people involved in making the decision. Salary administration / promotions can be viewed as favoritism but top performers with visible results are rewarded. To progress your career you need to move to multiple locations. Moving to different locations / work groups is challenging, both professionally and personally - all higher level management has done this.