Pros
A big company will have better access to valuable resources for each of their employee's learning and career development, and therefore in the long-term, it's their company and people who will benefit.
Kontras
Although you have a clearly defined role and the luxury of switching careers within the company, you might not be able to explore other projects beyond your scope of work, or even to pick up new skills. For example, it would be difficult for a graphic designer to explore the role of relationship management because those shoes have already been filled, and big companies are less likely to select someone who's never been trained in that field before.