Pros
Exciting products that you can feel associated with. You are given opportunities to work with smart, creative people. Depending on the team or job, in can be an exciting, challenging experience. Great campus and work environment at corporate headquarters.
Cons
Depending on the job, you may just get stuck implementing others' or management's decisions. You can get blind-sided by politics (re-orgs, program cuts, or even layoffs) No formal training available internally. Must learn on the job (if you are lucky) or find external means (classes, books, web) to learn or get experience with new technologies. Difficult to transfer internally to other positions - no career pathing this way -- you are on your own. HR offers little support in this area (perhaps they are powerless). Also, your boss can easily block a transfer if they choose.