Avantages
It's a big company, so there are options to choose from - moving groups is possible, even changing career tracks (Engineer to PM, etc.) is a possibility. The company is stable and won't be going away soon :) - as long you are doing a good job, there is little worry that you'll be laid off. The health and 401(k) benefits are generally decent. As always - combination of right place, right time, hard work, positive energy will pay off in the long term - have a 5 year + window.
Inconvénients
Its big! So a lot of people seem lost. My knowledge is limited to Fusion Middleware (Application Server) platform area and cannot comment of DB or APPS teams - the problems are - dysfunctional - there is the obvious "right arm doesn't know what left arm is doing" syndrome. - SDLC is not strictly followed -- engineering process gets a little chaotic/ ad hoc. the initial set of requirements/restrictions that you start with almost never hold true. Some thing or the other will change and you'll have to accommodate for it. - schedules are very aggressive but in my opinion not realistic. To give an example, product hasn't shipped 18 months after a previously advertised "code freeze" date. - you work a lot but get a sense of not having achieved as much. - if you like to code a lot, then this isn't the place :( - nobody makes firm commitments on requirements/schedules - I guess it is a way to make sure anything you don't know now can be made a "requirement" later.