Pros
Strong systems in place for standard large project execution, good (to great) packages offered to encourage personnel to join and stay, potential for lots of resources available to help when required (if the budget allows for them!), strong opportunities for mobility within the business if projects require it. Great focus on safety of personnel.
Cons
Somewhere between top-level corporate management and the execution of day-to-day business, all vestiges of any strong corporate vision are lost. Because of the multiple overlapping/interacting business sectors and the multiple levels of associated management, often it is not clear who is actually responsible to act for the business and get the job done. Multiple examples of business being lost or poorly executed because too few personnel, senior or otherwise, took ownership of even their own "bit". Those that do, often appear frustrated by the company structure and a corporate culture not rewarding of innovation, courage, or ingenuity.