Pros
Big company - lots of room for personal growth. Just go to school part time or something (they pay for it completely), get that degree, and then it really opens up many doors for you within that same company. And I think you have a better chance of getting hired on, better than outside folks.
Cons
Well, my particular job was pretty monotonous and boring...But I'm in school part time, hopefully I will finish pretty soon and get to do something more exciting. The HUGE downside is risk of layoffs. Not too stable. I'm getting laid off now after 15 months working here. But that means I get to use unemployment insurance and other benefits while studying full time - a little less financial worry here. So I guess my life might work out just fine.