Pros
Over-all the company is decent. They have a strong focus on culture and image. In principle, Shell promotes continious self development which involves, developing leadership attributes and improving your deficiencies. This is however only in principle. This usually involves filling out some paper work once a year with your manager and then never looked at again. Good place to start your career due to the training, and little to no responsibility. You will have lots of opportunity to ask questions and learn how a giant company operates.
Cons
Crippling processes that lead to extreme, and I mean extreme, inefficiency. The year involves one corporate review after another. Technical work is something you do in your spare time around endless forms, meetings, and process. Plays are entered late because of internal process, in 'left-over' areas. Management will then run economics to assess how much resource is needed to make the 'left-over' asset economic and then encourage staff to find long convoluted methods of achieving those numbers. This is all done in a save my job mentality.