Pros
Even though Shell is a global company with worldwide careers, the company has a strong local character in each location. No one size fits all mentality. It's therefore an easy place to work and fit in. Training and development for junior staff is probably best in industry. Generally very low turn-over of staff; stable company with above average job security in oil and gas.
Cons
Company struggles to combine global presence with local leadership. It's very common not to have your line manager in the same location (sometimes the other side of the world), leading to poor team dynamics and strong dependence on deputy leadership. Additionally, questions arise around the quality of performance reviews by line managers that have only very sparse personal interaction with their staff.