Pros
I think the best reason to work at Boeing is because of the projects that you can contribute to. The benefits are pretty good and the pay is up there with other large companies if you produce. I see younger engineers moving up as their desire and talents warrent. There isn't as much of the ol' boys network at Boeing anymore. Most of them have retired.
Cons
It's a big company, but you still can have a significant impact once you get established and get credibility. Occasionally you'll run across a manager that thinks he's God's gift to mankind and he won't listen to anyone because he's God and nobody else knows anything more than he does. There seems to be too much manage by MBA and too much nice guy management. Sometimes somebody just needs to be shown the door because they don't fit in (not enough motivation) but it doesn't happen, they end up working somewhere else in the company.